cas 57-10-3, Palmitic acid | Articles data

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A fluorometric assay for lysosomal phospholipase A2 activity using fluorescence-labeled truncated oxidized phospholipid
Lysosomal phospholipase A2 (LPLA2) is a key enzyme involved in the homeostasis of cellular phospholipids. Recently, LPLA2 was reported to preferentially degrade some truncated oxidized phospholipids at the sn-1 position. A commercially available, truncated oxidized phospholipid conjugated with a fluorescent dye, 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphoethanolamine-N-[4-(dipyrrometheneboron difluoride) butanoyl] (PGPE-BODIPY), was used to develop a specific assay for this enzyme. When recombinant mouse LPLA2 was incubated with liposomes consisting of 1,2-O-octadecyl-sn-glycero-3-phosphocholine/PGPE-BODIPY under acidic conditions, PGPE-BODIPY was converted to palmitic acid and a polar BODIPY-product. After phase partitioning by chloroform/methanol, the polar BODIPY-product was recovered in the aqueous phase and identified as 1-lyso-PGPE-BODIPY. The formation of 1-lyso-PGPE-BODIPY was quantitatively determined by fluorescent measurements. The Km and Vmax values of the recombinant LPLA2 for PGPE-BODIPY were 5.64 μM and 20.7 μmol/min/mg protein, respectively. Detectable activity against PGPE-BODIPY was present in LPLA2 deficient mouse sera, but the deacylase activity was completely suppressed by treatment with 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF). AEBSF had no effect on LPLA2 activity. The LPLA2 activity of mouse serum pre-treated with AEBSF was specifically and quantitatively determined by this assay method. The PGPE-BODIPY and AEBSF based LPLA2 assay is convenient and can be used to measure LPLA2 activity in a variety of biological specimens.
Abe, Akira,Hiraoka, Miki,Shayman, James A.,Ohguro, Hiroshi
p. 164 - 170
(2018)
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A new triterpenoid with antimicrobial activity from Anemone rivularis
A new triterpene ester 1 and six known triterpenoids were isolated from Anemone rivularis by repeated column chromatography. Their structures were identified as olean-9(11),12-dien-3-O-palmitate (1), lupeol (2), betulin (3), betulic acid (4), oleanolic acid (5), ursolic acid (6), and β-amyrin (7) by spectral analysis and comparison with the published data. In addition, compound 1 was evaluated in vitro for its antimicrobial activity. It was found to exhibit moderate activity against the Gram-positive bacteria B. subtilis and S. aureus.
Zhao, Chun-Chao,Shao, Jian-Hua,Fan, Ju-Di
p. 803 - 805
(2012)
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Synthesis and tissue biodistribution of [ω-11C]palmitic acid. A novel PET imaging agent for cardiac fatty acid metabolism
In order to diagnose patients with medium-chain acyl-CoA dehydrogenase deficiency with a noninvasive diagnostic technique such as positron emission tomography, we have developed a synthesis of [ω-11C]palmitic acid. The radiochemical synthesis was achieved by coupling an alkylfuran Grignard reagent (7) with [11C]methyl iodide, followed by rapid oxidative cleavage of the furan ring to the carboxylate using ruthenium tetraoxide. Tissue biodistribution studies in rats comparing [ω-11C]palmitic acid and [1- 11C]palmitic acid show that the %ID/g and %ID/organ in the heart tissue after administration of [ω-11C]palmitic acid is approximately 50% greater than after administration of [1-11C]palmitic acid, due to the diminished metabolism of the [ω-11C]palmitic acid. These studies show as well, low uptake in nontarget tissues (blood, lung, kidney, and muscle). PET images of a dog heart obtained after administration of [ω-11C] and [1- 11C]palmitic acid show virtually identical uptake and distribution in the myocardium. The differing cardiac washout of labeled palmitates measured by dynamic PET studies may allow diagnosis of disorders in cardiac fatty acid metabolism.
Buckman,VanBrocklin,Dence,Bergmann,Welch,Katzenellenbogen
p. 2481 - 2485
(1994)
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Shell-detachable nanoparticles based on a light-responsive amphiphile for enhanced siRNA delivery
Novel light-responsive nanoparticles based on an amphiphile with a single photolabile linker between its hydrophilic head and hydrophobic tail was developed for small interfering RNA (siRNA) delivery. Upon UV exposure, cleavage of the linkage resulted in rapid shell detachment of the nanoparticles, which facilitated siRNA release and enhanced gene silencing efficiency.
Li, Hong-Jun,Wang, Hong-Xia,Sun, Chun-Yang,Du, Jin-Zhi,Wang, Jun
p. 1961 - 1964
(2014)
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Anti-HIV1 Diterpenoids from Leaves and Twigs of Polyalthia sclerophylla
Bioassay-guided fractionation and purification of the anti-HIV-1-active MeOH extract from the leaves and twigs of Polyalthia sclerophylla led to the isolation of two new compounds, ent-kaur-sclerodimer (1) and cyclotucanol 3-palmitate (2), along with the known ent-kaur-16-en-19-oic acid (3), 15-hydroxy-ent-kaur-16-en-19-oic acid (4), 15-acetoxy-ent-kaur-16-en-19-oic acid (5), 15-oxo-ent-kaur-16-en-19-oic acid (6), 16,17-dihydroxy-ent-kauran-19-oic acid (7), 16-hydroxy-ent-kauran-19-oic acid (xylopic acid) (8), a pseudodimer (15-hydroxy-ent-kaur-16-en-19-oic acid/17-hydroxy-ent-kaur-15-en-19-oic acid) (9), ermanin, nicotiflorin, and allantoin. Among these isolates, compound 3 was the most active in both anti-syncytium (EC50 13.7μg/mL and selectivity index 3.1) and HIV-1 reverse transcriptase (IC50 34.1μg/mL) assays. Georg Thieme Verlag KG Stuttgart.
Saepou, Siriporn,Pohmakotr, Manat,Reutrakul, Vichai,Yoosook, Chalobon,Kasisit, Jitra,Napaswad, Chanita,Tuchinda, Patoomratana
p. 721 - 725
(2010)
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New diterpenoids from the roots of Euphorbia ebracteolata Hayata
Three new diterpenoids, ingenol-5,20-O,O-isopropylidene-3-palmitate (1), ingenol-5,20-O,O-isopropylidene-3-myristinate (2) and 3,19-dihydroxy-1(10),15- rosadien-2-one (3), were isolated from the roots of Euphorbia ebracteolata Hayata. Their structures wer
Deng, Bin,Mu, Shu-Zhen,Zhang, Jian-Xin,Hao, Xiao-Jiang
p. 1503 - 1509
(2010)
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Production of the anti-inflammatory compound 6-o-palmitoyl-3-O-β-D- glucopyranosylcampesterol by callus cultures of lopezia racemosa cav. (onagraceae)
Lopezia racemosa Cav. is a plant used in Mexican traditional medicine to heal inflammatory diseases. From this plant we isolated the novel compound 6-O-palmitoyl- 3-O-β-D-glucopyranosylcampesterol (1) and 6-O-palmitoyl-3-O-β-D-glucopyranosyl-β- sitosterol (2), previously reported to have cytotoxic activity on several cancer cell lines. We evaluated the anti-inflammatory activity of 1 in vivo by mouse ear edema induced with 12-O-tetradecanoylphorbol-13-acetate (TPA) and 57.14% inhibition was observed. The aim of our study was to obtain callus cultures derived from this plant species with the ability to produce the compounds of interest. Callus cultures were initiated on MS basal medium amended with variable amounts of naphthaleneacetic acid (NAA), or 2,4-dichlorophenoxyacetic acid (2,4-D), combined or not with 6-benzylaminopurine (BAP). Ten treatments with these growth regulators were carried out, using in vitro germinated seedlings as source of three different explants: hypocotyl, stem node, and leaf. Highest yield of 1 was observed on callus derived from leaf explants growing in medium containing 1.0 mg/L 2,4-D and 0.5 mg/L BAP. Selected callus lines produced less 1 than wild plants but the in vitro cultured seedlings showed higher production. So we conclude that it could be attractive to further investigate their metabolic potential.
Salinas, Roberta,Arellano-Garcia, Jesus,Perea-Arango, Irene,Alvarez, Laura,Garduno-Ramirez, Maria Luisa,Marquina, Silvia,Zamilpa, Alejandro,Castillo-Espana, Patricia
p. 8679 - 8690
(2014)
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Long-chain fatty acid acylated derivatives of isoflavone glycosides from the rhizomes of Iris domestica
Six undescribed long-chain fatty acid esters of isoflavone glycosides were obtained from the rhizomes of Iris domestica (L.). Their structures were elucidated by comprehensive spectroscopic data, alkaline hydrolysis, and acid hydrolysis. This is the first report of the long-chain (C14–C18) fatty acid derivatives of isoflavone glycosides from natural products. Belamcandnoate B and D exhibited moderate cytotoxic activities against HCT-116, HepG2, and BGC823 cell lines with IC50 values of 1.69–6.86 μM. Belamcandnoate B and E exhibited 72.27 and 58.98% inhibitory activities, respectively, against Fe2+/cysteine-induced liver microsomal lipid peroxidation at a concentration of 10 μM.
Li, Jiayuan,Liu, Yanfei,Ni, Gang,Wang, Renzhong,Yu, Dequan
(2021/11/01)

Biochemical and biophysical characterisation of a small purified lipase from Rhizopus oryzae ZAC3
The characteristics of a purified lipase from Rhizopus oryzae ZAC3 (RoL-ZAC3) were investigated. RoL-ZAC3, a 15.8 kDa protein, which was optimally active at pH 8 and 55 °C had a half-life of 126 min at 60 °C. The kinetic parameters using p-nitrophenylbuty
Ayinla, Zainab A.,Ademakinwa, Adedeji N.,Gross, Richard A.,Agboola, Femi K.
(2021/02/16)

Lipase mimetic cyclodextrins
Glycerophospholipids (GPLs) perform numerous essential functions in biology, including forming key structural components of cellular membranes and acting as secondary messengers in signaling pathways. Developing biomimetic molecular devices that can detect specific GPLs would enable modulation of GPL-related processes. However, the compositional diversity of GPLs, combined with their hydrophobic nature, has made it challenging to develop synthetic scaffolds that can react with specific lipid species. By taking advantage of the host-guest chemistry of cyclodextrins, we have engineered a molecular device that can selectively hydrolyze GPLs under physiologically relevant conditions. A chemically modified α-cyclodextrin bearing amine functional groups was shown to hydrolyze lyso-GPLs, generating free fatty acids. Lyso-GPLs are preferentially hydrolyzed when part of a mixture of GPL lipid species, and reaction efficiency was dependent on lyso-GPL chemical structure. These findings lay the groundwork for the development of molecular devices capable of specifically manipulating lipid-related processes in living systems.
Lee, Youngjun,Devaraj, Neal K.
p. 1090 - 1094
(2021/02/06)

Fabrication of dual catalytic microcapsules by mesoporous graphitic carbon nitride (mpg-C3N4) nanoparticle-enzyme conjugate stabilized emulsions
Emulsionlated microcapsules (MCs) were fabricated by simultaneous self-assembly and crosslinking of mpg-C3N4 nanoparticles (NPs) and lipase conjugates at an oil-water interface. The presence of both enzymes and mpg-C3Nsub
Varshney, Rohit,Kumar, Sushil,Ghosh, Kaushik,Patra, Debabrata
p. 3097 - 3102
(2020/03/03)

Calixarenes functionalised water-soluble iron oxide magnetite nanoparticles for enzyme immobilisation
In this study, we first used water-soluble iron oxide nanoparticles for Candida rugosa lipase immobilisation. Moreover, two new complexation phenomena of the prepared water-soluble Fe3O4 nanoparticles with an enzyme might address int
Sayin, Serkan,Ozyilmaz, Elif,Oguz, Mehmet,Yusufoglu, Rüstem,Yilmaz, Mustafa
p. 334 - 344
(2020/03/30)

Acceptorless dehydrogenative oxidation of primary alcohols to carboxylic acids and reduction of nitroarenes via hydrogen borrowing catalyzed by a novel nanomagnetic silver catalyst
A novel silver nano magnetic catalyst was devised for dehydrogenative oxidation of aromatic and aliphatic alcohols to the corresponding acid with water as the sole oxygen source and hydrogen gas as the only by-product. The designed catalytic system advantages from easy recovery of magnetic materials i.e. magnetic decantation, being economically viable and environmentally friendly. Furthermore, the catalytic reaction is able to reduce aryl nitro compounds in the absence of any reducing agent.
Yazdani, Elahe,Heydari, Akbar
supporting information

(2020/08/14)

Copper (II) immobilized on magnetically separable L-arginine-β-cyclodextrin ligand system as a robust and green catalyst for direct oxidation of primary alcohols and benzyl halides to acids in neat conditions
Copper (II) immobilized on L-arginine-β-cyclodextrin-functionalized magnetite nanoparticles (nano-Fe3O4@L-arginine-CD-Cu(II)) were successfully synthesized and fully characterized using FT-IR, XRD, SEM, EDX, ICP, TGA and VSM techniques. The catalytic activity of these magnetically retrievable nanoparticles was evaluated in the direct oxidation of primary alcohols and benzyl halides to acids in neat conditions that was observed to proceed well and products were obtained in good yields. In addition to showing good catalytic activity, the magnetic catalyst is easy to synthesize and can be recycled at least five times with little loss in activity.
Nejad, Masoumeh Jadidi,Salamatmanesh, Arefe,Heydari, Akbar
(2020/02/11)

Synthesis, molecular modeling and biological evaluation of metabolically stable analogues of the endogenous fatty acid amide palmitoylethanolamide
Palmitoylethanolamide (PEA) belongs to the class of N‐acylethanolamine and is an endogenous lipid potentially useful in a wide range of therapeutic areas; products containing PEA are licensed for use in humans as a nutraceutical, a food supplement, or food for medical purposes for its analgesic and anti‐inflammatory properties demonstrating efficacy and tolerability. However, the exogenously administered PEA is rapidly inactivated; in this process, fatty acid amide hydrolase (FAAH) plays a key role both in hepatic metabolism and in intracellular degradation. So, the aim of the present study was the design and synthesis of PEA analogues that are more resistant to FAAH-mediated hydrolysis. A small library of PEA analogues was designed and tested by molecular docking and density functional theory calculations to find the more stable analogue. The computational investigation identified RePEA as the best candidate in terms of both synthetic accessibility and metabolic stability to FAAH‐mediated hydrolysis. The selected compound was synthesized and assayed ex vivo to monitor FAAH‐mediated hydrolysis and to confirm its anti-inflammatory properties.1H‐NMR spectroscopy performed on membrane samples containing FAAH in integral membrane protein demonstrated that RePEA is not processed by FAAH, in contrast with PEA. Moreover, RePEA retains PEA’s ability to inhibit LPS‐induced cytokine release in both murine N9 microglial cells and human PMA‐THP‐1 cells.
D’aloia, Alessia,Arrigoni, Federica,Tisi, Renata,Palmioli, Alessandro,Ceriani, Michela,Artusa, Valentina,Airoldi, Cristina,Zampella, Giuseppe,Costa, Barbara,Cipolla, Laura
p. 1 - 25
(2020/12/02)

Identification and α -Glucosidase Inhibitory Activity of Meroterpenoids from Hericium erinaceus
Hericium erinaceus is a very popular edible and medicinal mushroom used for the treatment of enervation and gastrointestinal diseases in Eastern Asia. Chemical investigation on the fruiting body of Hericium erinaceus led to the isolation of 4 new (1 - 4) and 10 known meroterpenoids (5 - 14). The structures of new compounds were determined via analysis of NMR and MS data in combination with chemical derivatization. The inhibitory activities of 1 - 14 against α -glucosidase were evaluated using p -nitrophenyl- α -D-glucopyranoside, sucrose, or maltose as substrate. Compounds 6, 9, 11 - 13 were demonstrated to show the α -glucosidase inhibitory activities. This work confirms the potential of H. erinaceus in the treatment of diabetes.
Bao, Li,Chen, Baosong,Han, Junjie,Liu, Hongwei,Ma, Ke,Wang, Wenzhao
p. 571 - 578
(2020/06/03)

PROCESS FOR PRODUCING RENEWABLE PRODUCTS
The present invention relates to a method for producing renewable ketones, paraffin waxes, base oil components and alkenes from a feedstock of biological origin, wherein the method includes ketonisation of esters of fatty acids and monohydric alcohols wherein the alcohols have carbon chain length of two or more.
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Page/Page column 20-22

(2020/07/21)

The major zeaxanthin dipalmitate derivatives from wolfberry
Zeaxanthin dipalmitate (3) and two zeaxanthin dipalmitate derivatives, including one new compound (1), were obtained from wolfberry [the fruit of Lycium barbarum L. (Solanaceae)]. Their structures were unambiguously elucidated by spectroscopic analyses. Compound 2 is isolated from the genus Lycium for the first time, and its 1D/2D NMR data are firstly reported. All the compounds belong to carotenoids which are a kind of major bioactive constituents in wolfberry and are also responsible for wolfberry’s red color.
Long, Jia-Tang,Fan, Hong-Xia,Zhou, Zheng-Qun,Sun, Wan-Yang,Li, Qing-Wen,Wang, Ying,Ma, Min,Gao, Hao,Zhi, Hui
p. 746 - 753
(2019/06/17)

Substrate hydrophobicity and enzyme modifiers play a major role in the activity of lipase from: Thermomyces lanuginosus
Lipase from Thermomyces lanuginosus (TL) displays high affinity for long-chain substrates, such as triolein and other long-chain triacylglycerols. Aiming to broaden the substrate chain-length specificity, different aldehydes (naphthaldehyde, butyraldehyde, hexyl aldehyde and dodecyl aldehyde) and naphthyl isothiocyanate were grafted onto lipase TL through lysine coupling. The catalytic activity of the modified lipases was investigated by reaction with substrates differing in the aliphatic chain size (p-nitrophenyl benzoate, p-nitrophenyl acetate, p-nitrophenyl butyrate, p-nitrophenyl hexanoate, p-nitrophenyl octanoate, p-nitrophenyl laurate and p-nitrophenyl palmitate). The enzymes modified with aldehydes revealed higher activity than the enzymes modified with the isothiocyanate. The most notable results were achieved for lipase TL grafted with 4 units of a dodecyl chain (TL5), which revealed the highest activity against all the tested substrates, being 10-fold more active than the native enzyme for smaller substrates (acetate and butyrate chains) and 2-fold for longer substrates (laurate and palmitate chains). The kinetic parameters evaluated (Vmax, KM and kcat/KM) also confirmed the significant catalytic performance of TL5 compared to the native enzyme. The increase in activity revealed by the modified lipases was directly proportional to the size and hydrophobicity of the linkers' aliphatic chain. Small conformational changes, either on the enzyme's lid or on the cavity of the active site were suggested by molecular dynamics simulations, circular dichroism and fluorescence spectroscopy. Moreover, the grafting with aldehydes or with the isothiocyanate conferred higher thermostability to the lipase. The chemical surface modification developed efficiently improved the activity of lipase TL, broadening the substrate's chain-length specificity, increasing thereafter the substrate possibilities for industrial reactions. This journal is
Castro, Tarsila G.,Cavaco-Paulo, Artur,Noro, Jennifer,Silva, Carla
p. 5913 - 5924
(2020/10/08)

Multiscale immobilized lipase for rapid separation and continuous catalysis
Enzyme-inorganic hybrid nanoflowers have drawn extensive research interest for enzyme immobilization owing to their enhanced enzymatic activity, high surface area, and excellent chemical stability. However, their low mechanical stability and challenging s
Ren, Weifan,Fei, Xu,Tian, Jing,Li, Yao,Jing, Muzi,Fang, Huan,Xu, Longquan,Wang, Yi
supporting information
p. 13471 - 13478
(2018/08/21)

Mild alkaline hydrolysis of hindered esters in non-aqueous solution
Sterically hindered esters of carboxylic acids, which are considered very resistant to saponification, were rapidly and efficiently saponified in a non-aqueous medium using NaOH in MeOH/CH2Cl2 (1:9) at room temperature. Furthermore, this reaction protocol was extended and successfully applied to the hydrolysis of tosylates and N-tosyl indoles.
Theodorou, Vassiliki,Alagiannis, Michalis,Ntemou, Nikoleta,Brentas, Alexios,Voulgari, Pinelopi,Polychronidou, Vasiliki,Gogou, Marina,Giannelos, Marios,Skobridis, Konstantinos
p. 308 - 319
(2018/11/26)

Alteration of Chain Length Selectivity of Candida antarctica Lipase A by Semi-Rational Design for the Enrichment of Erucic and Gondoic Fatty Acids
Biotechnological strategies using renewable materials as starting substrates are a promising alternative to traditional oleochemical processes for the isolation of different fatty acids. Among them, long chain mono-unsaturated fatty acids are especially interesting in industrial lipid modification, since they are precursors of several economically relevant products, including detergents, plastics and lubricants. Therefore, the aim of this study was to develop an enzymatic method in order to increase the percentage of long chain mono-unsaturated fatty acids from Camelina and Crambe oil ethyl ester derivatives, by using selective lipases. Specifically, the focus was on the enrichment of gondoic (C20:1 cisΔ11) and erucic acid (C22:1 cisΔ13) from Camelina and Crambe oil derivatives, respectively. The pursuit of this goal entailed several steps, including: (i) the choice of a suitable lipase scaffold to serve as a protein engineering template (Candida antarctica lipase A); (ii) the identification of potential amino acid targets to disrupt the binding tunnel at the adequate location; (iii) the design, creation and high-throughput screening of lipase mutant libraries; (iv) the study of the selectivity towards different chain length p-nitrophenyl fatty acid esters of the best hits found, as well as the analysis of the contribution of each amino acid change and the outcome of combining several of the aforementioned residue alterations and, finally, (v) the selection and application of the most promising candidates for the fatty acid enrichment biocatalysis. As a result, enrichment of C22:1 from Crambe ethyl esters was achieved either, in the free fatty acid fraction (wt, 78%) or in the esterified fraction (variants V1, 77%; V9, 78% and V19, 74%). Concerning the enrichment of C20:1 when Camelina oil ethyl esters were used as substrate, the best variant was the single mutant V290W, which doubled its content in the esterified fraction from approximately 15% to 34%. A moderately lower increase was achieved by V9 and its two derived triple mutant variants V19 and V20 (27%). (Figure presented.).
Zorn, Katja,Oroz-Guinea, Isabel,Brundiek, Henrike,D?rr, Mark,Bornscheuer, Uwe T.
p. 4115 - 4131
(2018/10/02)

Iron-Catalyzed Aerobic Oxidation of Aldehydes: Single Component Catalyst and Mechanistic Studies
An aerobic oxidation of aldehydes towards carboxylic acids in MeCN using 1 atm of pure oxygen or oxygen in air as the oxidant and a catalytic amount of single component catalyst, Fe(NO3)3·9H2O, has been developed. Carboxylic acids with different synthetically useful functional groups were obtained at room temperature. Two mechanistic pathways have been proposed based on isotopic labeling, NMR monitoring, and control experiments. The practicality of this reaction has been demonstrated by conducting several 50 mmol-scale reactions using pure oxygen or an air-flow of ~30 mL/min.
Jiang, Xingguo,Zhai, Yizhan,Chen, Junyu,Han, Yulin,Yang, Zheng,Ma, Shengming
supporting information
p. 15 - 19
(2017/11/23)

Fatty acid eutectic mixtures and derivatives from non-edible animal fat as phase change materials
A set of compounds from non-edible fat waste was prepared and their thermal behavior was studied. The fat was hydrolyzed and crystallized in a simple and robust process to yield palmitic acid-stearic acid (PA-SA) mixtures. The PA-SA mass ratios determined by GC-FID (gas chromatography-flame ionization detection) were similar to those reported for eutectic mixtures of PCMs (phase change materials). DSC (differential scanning calorimetry) results indicated that the melting and solidification temperatures were around 55 °C and 52 °C and the latent heat of the crystallized fractions measured was around 180 kJ kg-1. The thermal cycling reliability of the eutectic mixtures was also tested during 1000 melting/freezing cycles. The loss in melting and solidification enthalpies was below 14% in all mixtures showing a promising behavior for PCM applications. Additionally, the unsaturated fatty acids were recovered and transformed to threo-9,10-dihydroxystearic acid (DHSA) and some of their inorganic salts, which were analyzed by FT-IR (Fourier transform-infrared spectroscopy) and tested for the first time using the DSC technique.
Gallart-Sirvent, Pau,Martín, Marc,Villorbina, Gemma,Balcells, Mercè,Solé, Aran,Barrenche, Camila,Cabeza, Luisa F.,Canela-Garayoa, Ramon
p. 24133 - 24139
(2017/07/10)

Method for preparing acid through oxidating alcohols or aldehydes by oxygen
The invention provides a method for preparing acid through oxidating alcohols or aldehydes by using oxygen or oxygen in air as an oxidant. The method comprises the steps: oxidating the alcohols or aldehydes to produce the acid at room temperature in an organic solvent in a manner of taking ferric nitrate (Fe(NO3)3.9H2O), 2,2,6,6-tetramethylpiperidyl nitrogen oxide (TEMPO) and an inorganic halide as catalysts and taking the oxygen or air as an oxidant, and oxidating diols to produce lactone; or, carrying out a reaction on the aldehydes, which serve as a raw material, under neutral conditions by taking ferric nitrate as a catalyst, and oxidating the aldehydes to produce the acid and peroxy acid. The method has the advantages that the method is environmentally friendly, the cost is low, the yield is high, the atomic economical efficiency is high, the compatibility of substrate functional groups is good, the reaction conditions are mild, a reaction scale can be enlarged, and the like, so that the method is suitable for being applied to industrial production.
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Paragraph 0051; 0052; 0053; 0054; 0061; 0062-0063; 0166-0177

(2017/09/29)

Characterization of homologous sphingosine-1- phosphate lyase isoforms in the bacterial pathogen Burkholderia pseudomallei
Sphingolipids (SLs) are ubiquitous elements in eukaryotic membranes and are also found in some bacterial and viral species. As well as playing an integral structural role, SLs also act as potent signaling molecules involved in numerous cellular pathways and have been linked to many human diseases. A central SL signaling molecule is sphingosine-1-phosphate (S1P), whose breakdown is catalyzed by S1P lyase (S1PL), a pyridoxal 5?-phosphate (PLP)-dependent enzyme that catalyzes the cleavage of S1P to (2E)-hexadecenal (2E-HEX) and phosphoethanolamine. Here, we show that the pathogenic bacterium, Burkholderia pseudomallei K96243, encodes two homologous proteins (S1PL2021 and S1PL2025) that display moderate sequence identity to known eukaryotic and prokaryotic S1PLs. Using an established MS-based methodology, we show that recombinant S1PL2021 is catalytically active. We also used recombinant human fatty aldehyde dehydrogenase to develop a spectrophotometric enzymecoupled assay to detect 2E-HEX formation and measure the kinetic constants of the two B. pseudomallei S1PL isoforms. Furthermore, we determined the X-ray crystal structure of the PLP-bound form of S1PL2021 at 2.1 ? resolution revealing that the enzyme displays a conserved structural fold and active site architecture comparable with known S1PLs. The combined data suggest that B. pseudomallei has the potential to degrade host SLs in a S1PL-dependent manner.-McLean, C., J. Marles-Wright, R. Custodio, J. Lowther, A. J. Kennedy, J. Pollock, D. J. Clarke, A. R. Brown, and D. J. Campopiano. Characterization of homologous sphingosine-1-phosphate lyase isoforms in the bacterial pathogen Burkholderia pseudomallei.
McLean, Christopher J.,Marles-Wright, Jon,Custodio, Rafael,Lowther, Jonathan,Kennedy, Amanda J.,Pollock, Jacob,Clarke, David J.,Brown, Alan R.,Campopiano, Dominic J.
p. 137 - 150
(2017/01/25)

Iron Catalysis for Room-Temperature Aerobic Oxidation of Alcohols to Carboxylic Acids
Oxidation from alcohols to carboxylic acids, a class of essential chemicals in daily life, academic laboratories, and industry, is a fundamental reaction, usually using at least a stoichiometric amount of an expensive and toxic oxidant. Here, an efficient and practical sustainable oxidation technology of alcohols to carboxylic acids using pure O2 or even O2 in air as the oxidant has been developed: utilizing a catalytic amount each of Fe(NO3)3·9H2O/TEMPO/MCl, a series of carboxylic acids were obtained from alcohols (also aldehydes) in high yields at room temperature. A 55 g-scale reaction was demonstrated using air. As a synthetic application, the first total synthesis of a naturally occurring allene, i.e., phlomic acid, was accomplished.
Jiang, Xingguo,Zhang, Jiasheng,Ma, Shengming
supporting information
p. 8344 - 8347
(2016/07/26)

Hydrodeoxygenation of methyl palmitate over MCM-41 supported nickel phosphide catalysts
In this paper, bulk and MCM-41-supported Ni2P catalysts were synthesized by the one-step direct reduction of metal phosphate precursors. The role of cations and anions in the synthesis of Ni2P was studied. Catalytic properties for the hydrodeoxygenation (HDO) of methyl palmitate were first investigated in a continuous-flow fixed-bed microreactor. The resulting catalysts were characterized using XRD, TEM, BET, XPS, and carbon monoxide chemisorption. Results indicated that Ni2P can be synthesized at 600 °C from its phosphate precursors with a mole ratio of Ni/P = 2/1. Based on the analytical result of GC-MS, we propose a possible HDO reaction mechanism for the HDO of methyl palmitate on MCM-41-supported nickel phosphide catalysts.
Guan, Qingxin,Wan, Fanfan,Han, Fei,Liu, Zihe,Li, Wei
p. 467 - 473
(2015/11/10)

Additional nucleophile-free FeCl3-catalyzed green deprotection of 2,4-dimethoxyphenylmethyl-protected alcohols and carboxylic acids
The deprotection of the methoxyphenylmethyl (MPM) ether and ester derivatives can be generally achieved by the combinatorial use of a catalytic Lewis acid and stoichiometric nucleophile. The deprotections of 2,4-dimethoxyphenylmethyl (DMPM)-protected alcohols and carboxylic acids were found to be effectively catalyzed by iron(III) chloride without any additional nucleophile to form the deprotected mother alcohols and carboxylic acids in excellent yields. Since the present deprotection proceeds via the self-assembling mechanism of the 2,4-DMPM protective group itself to give the hardly-soluble resorcinarene derivative as a precipitate, the rigorous purification process by silica-gel column chromatography was unnecessary and the sufficiently-pure alcohols and carboxylic acids were easily obtained in satisfactory yields after simple filtration.
Sawama, Yoshinari,Masuda, Masahiro,Honda, Akie,Yokoyama, Hiroki,Park, Kwihwan,Yasukawa, Naoki,Monguchi, Yasunari,Sajiki, Hironao
p. 778 - 784
(2016/07/16)

NOVEL GENE DERIVED FROM MUD FLAT METAGENOME AND NOVEL PROTEIN OBTAINED THEREFROM SHOWING COACTIVITY OF PHOSPHOLIPASE AND LIPASE
The present invention relates to a novel gene derived from a tidal flat metagenome, and a novel protein obtained therefrom showing the coactivity of phospholipase and lipase. Specifically, the novel gene isolated from the metagenome library of tidal flat sedimentsand the protein having phospholipase and lipase activities encoded from the novel gene: are expressed in a water-soluble form to be mass-producible; enable ultra high-purity protein to be obtained through single step purification using an Ni-NTA column; show good activity in the pH range of 5 ?? 10; maintain good low temperature activity and stability up to a temperature of 3°C to 40°C; and have high resistance against various organic solvents. Therefore, the novel gene and the protein can be usefully used for various industrial fields such as the purification and conversion of oil and fat, bio-medicine, and fine chemistry.
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Paragraph 0083-0084

(2016/03/14)

Effect of precursor on the catalytic properties of Ni2P/SiO2 in methyl palmitate hydrodeoxygenation
The effect of phosphorus precursor on the physicochemical and catalytic properties of silica-supported nickel phosphide catalysts in the hydrodeoxygenation (HDO) of aliphatic model compound methyl palmitate (C15H31COOCH3) has been considered. Nickel aceta
Shamanaev, Ivan V.,Deliy, Irina V.,Aleksandrov, Pavel V.,Gerasimov, Evgeny Yu.,Pakharukova, Vera P.,Kodenev, Evgeny G.,Ayupov, Artem B.,Andreev, Andrey S.,Lapina, Olga B.,Bukhtiyarova, Galina A.
p. 30372 - 30383
(2017/02/23)

Hydrodeoxygenation (HDO) of methyl palmitate over bifunctional Rh/ZrO2 catalyst: Insights into reaction mechanism via kinetic modeling
Hydrodeoxygenation (HDO) of triglycerides into hydrocarbons is a novel catalytic process for the production of green biofuels. In this work, the HDO reaction mechanism over Rh/ZrO2 catalyst was studied by selecting methyl palmitate as a model compound. HDO of methyl palmitate proceeded initially via the hydrogenolysis into palmitic acid intermediate, followed by sequential hydrogenation-decarbonylation reaction into pentadecane via aldehyde intermediate. Bifunctional mechanism of the Rh/ZrO2 catalyst is advocated for the HDO process, in which both Rh sites and oxygen vacancy sites on ZrO2 synergistically contribute to the catalysis. The interface between Rh nanoparticle and support was proposed to host the most active sites. Based on our earlier work, a surface reaction mechanism was proposed and slightly modified to develop a set of mechanistic kinetic models. The mechanistic model consisting of two distinct types of adsorption sites for oxygenated components and H2, gave a good fitting to the kinetic data over a broad range of reaction conditions and conversion levels.
Bie, Yuwei,Lehtonen, Juha,Kanervo, Jaana
p. 183 - 190
(2016/09/13)

Lipase-supported metal-organic framework bioreactor catalyzes warfarin synthesis
A green and sustainable strategy synthesizes clinical medicine warfarin anticoagulant by using lipasesupported metal-organic framework (MOF) bioreactors (see scheme). These findings may be beneficial for future studies in the industrial production of chemical, pharmaceutical, and agrochemical precursors
Liu, Wan-Ling,Yang, Ni-Shin,Chen, Ya-Ting,Lirio, Stephen,Wu, Cheng-You,Lin, Chia-Her,Huang, Hsi-Ya
supporting information
p. 115 - 119
(2015/10/12)

Activity of neutral and alkaline ceramidases on fluorogenic N -acylated coumarin-containing aminodiols
Ceramidases catalyze the cleavage of ceramides into sphingosine and fatty acids. Previously, we reported on the use of the RBM14 fluorogenic ceramide analogs to determine acidic ceramidase activity. In this work, we investigated the activity of other amidohydrolases on RBM14 compounds. Both bacterial and human purified neutral ceramidases (NCs), as well as ectopically expressed mouse neutral ceramidase hydrolyzed RBM14 with different selectivity, depending on the N -acyl chain length. On the other hand, microsomes from alkaline ceramidase (ACER)3 knockdown cells were less competent at hydrolyzing RBM14C12, RBM12C14, and RBM14C16 than controls, while microsomes from ACER2 and ACER3 overexpressing cells showed no activity toward the RBM14 substrates. Conversely, N -acylethanolamine-hydrolyzing acid amidase (NAAA) overexpressing cells hydrolyzed RBM14C14 and RBM14C16 at acidic pH. Overall, NC, ACER3, and, to a lesser extent, NAAA hydrolyze fluorogenic RBM14 compounds. Although the selectivity of the substrates toward ceramidases can be modulated by the length of the N -acyl chain, none of them was specific for a particular enzyme. Despite the lack of specificity, these substrates should prove useful in library screening programs aimed at identifying potent and selective inhibitors for NC and ACER3.
Casasampere, Mireia,Camacho, Luz,Cingolani, Francesca,Casas, Josefina,Egido-Gabás, Meritxell,Abad, José Luís,Bedia, Carmen,Xu, Ruijuan,Wang, Kai,Canals, Daniel,Hannun, Yusuf A.,Mao, Cungui,Fabrias, Gemma
p. 2019 - 2028
(2015/11/17)

Facile and selective deprotection of PMB ethers and esters using oxalyl chloride
Oxalyl chloride, (0.5 equiv) was found to cleave the PMB group from alkyl, aryl PMB ethers, and esters to give corresponding alcohol and acid in good yields. This method offers simple and efficient protocol for the selective deprotection of PMB ether and ester in DCE at ambient temperature.
Ilangovan, Andivelu,Anandhan, Karnambaram,Kaushik, Mahabir Prasad
p. 1081 - 1084
(2015/02/19)

Lid hinge region of Penicillium expansum lipase affects enzyme activity and interfacial activation
Saturation mutagenesis at sites displaying the highest B factors in the lid and the hinge regions of Penicillium expansum lipase (PEL) has been employed to improve the efficiency of the lipase in biocatalysis. Replacements of amino acid on beneficial mutants were identified as T66L/D70N, T66V/D70N, E83K, E83H and E83N. In substrate specificity assays, T66L/D70N was significantly more active than wild-type PEL on substrates with medium and long chain lengths. In addition this mutant also displayed a 136.4-fold increase in activity on p-nitrophenyl palmitate. Remarkably, E83K lacked interfacial activation while it was observed in wild-type PEL and the other mutants. Insight into the relation between the mutations and enzymatic properties was gained by modeling and docking studies. All these mutants showed an enhanced catalytic activity, indicating their potential in further application. Therefore, these results indicate the amino acid composition of the lid hinge region plays an extremely important role in the interfacial activation, activity and substrate specificity of PEL. Moreover, the results in this work provide a new clue for selecting critical amino acid residues for the enzyme design.
Tang, Lianghua,Su, Min,Yan, Junzhe,Xie, Sheng,Zhang, Wenhuang
p. 1218 - 1223
(2015/07/02)

A high-detergent-performance, cold-adapted lipase from Pseudomonas stutzeri PS59 suitable for detergent formulation
A high-detergent-performance and cold-adapted lipase was purified and characterised from Pseudomonas stutzeri PS59, which was isolated from Daqing oil fields (Heilongjiang, PR China). The lipase was purified to homogeneity using ammonium sulphate precipitation, dialysis, freeze-drying, ion exchange chromatography and gel filtration chromatography. The molecular weight of the lipase was approximately 55 kDa, as measured by SDS-PAGE. The lipase showed optima activity at pH 8.5 and 20 C. The lipase activity was activated by metal ions, such as Ca2+ and Mn2+, and surfactants, such as Tween 80, Tween 20, sodium dodecyl benzene sulfonate and urea. Oxidising agents, such as H2O2 and NaClO, were found to have little effect on the activity of the lipase, and most organic solvents can enhance the activity of the lipase. The broad substrate specificity and the compatibility of the lipase in the presence of surfactants, oxidising agents, and other detergent additives clearly indicate its potential application in the laundry industry. The hydrolysis resolution of (R,S)-ethyl 2-methylbutyrate by P. stutzeri PS59 lipase was carried out with the yield of 31.2% for R-ethyl 2-methylbutyrate, the enantiomeric excess of residual substrate (ees) was 85.7%. Thus, the lipase also showed an attractive potency for application in biocatalysis.
Li, Xiao-Lu,Zhang, Wen-Hui,Wang, Ying-Dong,Dai, Yu-Jie,Zhang, Hui-Tu,Wang, Yue,Wang, Hai-Kuan,Lu, Fu-Ping
p. 16 - 24
(2014/03/21)

Characterization of a novel hormone-sensitive lipase family esterase from Rhizomucor miehei with tertiary alcohol hydrolysis activity
A novel esterase gene (designated RmEstB) from the thermophilic fungus Rhizomucor miehei was cloned and functionally expressed in Escherichia coli. Sequence analysis revealed a 960-bp open reading frame encoding a protein of 319 amino acids. The deduced protein sequence contained an HGGG motif, suggesting that the enzyme is a hormone-sensitive lipase (HSL) family esterase. It showed highest identity of 52% with the esterase from Pseudomonas mandelii. The recombinant esterase was purified to homogeneity at 5.1-fold purification with a recovery yield of 85%. The molecular mass of RmEstB was estimated to be 37 kDa by SDS-PAGE. RmEstB was most active at pH 7.5 and 50 °C. The enzyme was highly stable in the presence of 30% ethanol, methanol, acetone, isopropanol, dimethyl sulfoxide and acetonitrile. RmEstB showed a broad range of substrate specificities toward various p-nitrophenol (pNP) esters (C2-C10) and triglycerides (C2-C6), with the highest specific activities obtained for pNP acetate (255 U/mg) and triacetin (1330 U/mg), respectively. In addition, RmEstB efficiently catalyzed the hydrolysis of sterically hindered esters of tertiary alcohols. This study presents a novel fungal HSL family esterase with potential for some industrial applications.
Yan, Qiao-Juan,Yang, Shao-Qing,Duan, Xiao-Jie,Xu, Hai-Bo,Liu, Yu,Jiang, Zheng-Qiang
p. 76 - 84
(2014/12/10)

Hydrodeoxygenation of methyl palmitate over sulfided Mo/Al 2O3, CoMo/Al2O3 and NiMo/Al 2O3 catalysts
The catalytic properties of sulfided Mo/Al2O3, CoMo/Al2O3 and NiMo/Al2O3 catalysts in the hydrodeoxygenation of methyl palmitate as a model compound for triglyceride feedstock were studied at 300°C and 3.5 MPa in the batch reactor using n-tetradecane, m-xylene and hydrotreated straight-run gas oil (HT-SRGO). The comparison of catalyst's performance in n-tetradecane allowed us to see that the sulfided Mo/Al2O3, CoMo/Al 2O3 and NiMo/Al2O3 catalysts revealed the same rate of the methyl palmitate conversion but the rate of the intermediate oxygenates conversion decreased in order: CoMoS/Al 2O3 > NiMoS/Al2O3 > MoS 2/Al2O3. A mixture of linear saturated and unsaturated C15 and C16 hydrocarbons was produced when the oxygenates were fully consumed. The main products obtained over the Mo/Al 2O3 and CoMo/Al2O3 catalysts were C16 hydrocarbons (C16/C15-16.1 and 2.79, respectively); however, C15 hydrocarbons were preferentially formed over the NiMo/Al2O3 catalyst (C16/C 15-0.65), highlighting the different contributions of the hydrodeoxygenation (HDO) and decarboxylation/decarbonylation (DeCOx) pathways during the hydroconversion of methyl palmitate over these catalysts. Investigating the solvent's influence on the activity of the CoMo/Al 2O3 and NiMo/Al2O3 catalysts in the methyl palmitate HDO revealed that the reaction rate was decreased in the following order: n-tetradecane > HT-SRGO > m-xylene. The aromatic compounds did not retard the methyl palmitate transformation, but inhibited the conversion of the intermediate oxygenates. Decreased C16/C 15 ratios were observed over both catalysts when m-xylene was used as the reaction medium instead of n-tetradecane.
Deliy, Irina V.,Vlasova, Evgenia N.,Nuzhdin, Alexey L.,Gerasimov, Evgeny Yu.,Bukhtiyarova, Galina A.
p. 2242 - 2250
(2014/01/06)

METHOD FOR PRODUCING CARBOXYLIC ACID AND ALCOHOL BY HYDROLYSIS OF ESTER
As shown by the following formula (1), after methyl laurate (2 mmol) and water (8 mL) are added to an ammonium pyrosulfate catalyst (5 mol%), a hydrolysis reaction of methyl laurate is carried out by heating for 24 hours at 60°C while stirring is performed, so that lauric acid can be obtained with a yield of 86%.
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Paragraph 0063; 0064; 0065

(2014/11/13)

Cloning, expression, purification, and characterization of a thermostable esterase from the archaeon Sulfolobus solfataricus P1
A genomic library of the thermoacidophilic archaeon Sulfolobus solfataricus P1 was constructed using 3.5 kb BamHI-fragments into pUC118 vector and the recombinant plasmids were hosted in Escherichia coli. One positive clone showing thermostable esterase a
Nam, Jae-Kyung,Park, Young-Jun,Lee, Hee-Bong
p. 95 - 103
(2013/10/22)

Characterization of a novel thermophilic pyrethroid-hydrolyzing carboxylesterase from Sulfolobus tokodaii into a new family
A novel gene ST2026 encoding a putative carboxylesterase from the thermophilic crenarchaeota Sulfolobus tokodaii (named EstSt7) was cloned and functionally overexpressed in Escherichia coli. The recombinant enzyme was purified to homogeneity after heat treatment, Ni-NTA affinity and Superdex-200 gel filtration chromatography. EstSt7 showed maximum activity at 80 C over 30 min and had a half-life of 180 min at 90 C. Its enzymatic activity was stable in the pH range of 8.0-10.0 with an optimum at 9.0. The enzyme exhibited significant esterase activity toward various p-nitrophenyl esters and the most preferable substrate was p-nitrophenyl butyrate (kcat/Km of 246.3 s-1 mM-1). In addition, EstSt7 showed high activity and stability against organic solvents (20% and 50% v/v) and detergents (1% and 5% v/v). Furthermore, EstSt7 could efficiently hydrolyze a wide range of synthetic pyrethroids including fenpropathrin, permethrin, cypermethrin, cyhalothrin, deltamethrin and bifenthrin, which makes it a potential candidate for the detoxification of pyrethroids for the purpose of biodegradation. Sequence alignment, phylogenetic analysis and comparison of the conserved motif reveal that this novel carboxylesterase EstSt7 should be grouped into a new bacterial lipase and esterase family.
Wei, Tao,Feng, Shengxue,Shen, Yulong,He, Peixin,Ma, Geli,Yu, Xuan,Zhang, Fei,Mao, Duobin
p. 225 - 232
(2013/10/21)

Enhancing catalytic performance of porcine pancreatic lipase by covalent modification using functional ionic liquids
Various functional ionic liquids (ILs) composed of different cations and anions were activated with carbonyldiimidazole and then covalently linked onto porcine pancreatic lipase (PPL) through lysine coupling. Catalytic performances, such as activity, thermostability, and enantioselectivity were improved successfully, as was investigated in p-nitrophenyl palmitate (pNPP) hydrolysis and racemic 1-phenethyl acetate hydrolysis reaction. The correlation between catalytic performance and modification of IL was studied by catalytic and spectroscopic data, which showed improvement of catalytic performances to a different extent. Hydrolytic activity was enhanced by ILs with chaotropic cations and kosmotropic anions (e.g., more than 4-fold with [choline][H 2PO4]). Modifications by ILs bearing kosmotropic cations and chaotropic anions contribute to lipase thermostability and enantioselectivity (e.g., modification with [HOOCBMIm][Cl] showed a 12-fold thermostability increase at 60 C and more than 7-fold enantioselectivity enhancement than native enzyme). The Matrix-assisted laser desorption/ ionization-time-of-flight mass spectrometry experiments suggest that ILs bind with lipase protein. Conformation changes were confirmed by fluorescence spectroscopy, and circular dichroism spectroscopy.
Jia, Ru,Hu, Yi,Liu, Luo,Jiang, Ling,Zou, Bin,Huang, He
p. 1976 - 1983
(2013/09/24)

A convenient approach for the deprotection and scavenging of the PMB group using POCl3
A convenient and high yielding approach for the deprotection and scavenging of the p-methoxybenzyl (PMB) group in PMB ethers and PMB esters was developed using POCl3 as the reagent. 4-Methoxybenzyl chloride, a starting material used for the preparation of PMB ethers and esters was regenerated in the deprotection step. This mild and selective procedure tolerates several acid sensitive functional groups. The Royal Society of Chemistry 2013.
Ilangovan, Andivelu,Saravanakumar, Shanmugasundar,Malayappasamy, Subramani,Manickam, Govindaswamy
p. 14814 - 14828
(2013/09/02)

New chemical constituents from oryza sativa straw and their algicidal activities against blue-green algae
Five new constituents, 5,4′-dihydroxy-7,3′-dimethoxyflavone- 4′-O-β-d-xylopyranosyl-(2a→1b)-2a-O-β-d-xylopyranosyl- (2b→1c)-2b-O-β-d-xylopyranosyl-2c-octadecanoate (1), 5,4′-dihydroxy-7,3′-dimethoxyflavone-4′-O-α-d- xylopyranosyl-(2a→1b)-2a-O-α-d-xylopyranosyl-(2b→1c) -2b-O-α-d-xylopyranosyl-(2c→1d)-2c-O-α-d-xylopyranosyl-2d- octadecanoate (2), kaempferol-3-O-α-d-xylopyranosyl-(2a→1b)-2a-O- α-d-xylopyranosyl-(2b→1c)-2b-O-α-d-xylopyranosyl-(2c→1d) -2c-O-α-d-xylopyranosyl-2d-hexadecanoate (3), methyl salicylate-2-O- α-d-xylopyranosyl-(2a→1b)-2a-O-α-d-xylopyranosyl-(2b→1c) -2b-O-α-d-xylopyranosyl-(2c→1d)-2c-O-α-d-xylopyranosyl- (2d→1e)-2d-O-α-d-xylopyranosyl-(2e→1f)-2e-O-α-d- xylopyranosyl-(2f→1g)-2f-O-α-d-xylopyranosyl-(2g→1h) -2g-O-α-d-xylopyranosyl-2h-geranilan-8′,10′-dioic acid-1′-oate (4), and oleioyl-β-d-arabinoside (5), along with eight known compounds, were isolated from a methanol extract of Oryza sativa straw. The structures of the new compounds were elucidated using one- and two-dimensional NMR spectroscopies in combination with IR, ESI/MS, and HR-ESI/FTMS. In bioassays with blue-green algae, the efficacies of the algicidal activities of the five new compounds (1-5) were evaluated at concentrations of 1, 10, and 100 mg/L. Compound 5 had the highest growth inhibition (92.6 ± 0.3%) for Microcystis aeruginosa UTEX 2388 at a concentration of 100 ppm (mg/L). Compound 5 has high potential for the ecofriendly control of weeds and algae harmful to water-logged rice.
Ahmad, Ateeque,Kim, Seung-Hyun,Ali, Mohd,Park, Inmyoung,Kim, Jin-Seog,Kim, Eun-Hye,Lim, Ju-Jin,Kim, Seul-Ki,Chung, Ill-Min
p. 8039 - 8048
(2013/09/23)

Diterpenic labdane galactofuranosides from the roots of Calotropis procera (Ait.) R. Br.
Two labdane-type diterpenic galactosides characterized as labdan-18-ol-b-D-galactofuranoside 4 and labdan-3β-ol- 11,15-olide-18,20- dioic acid-3β-D-glactofuranoside 5 have been isolated for the first time from the roots of Calotropis procera (Ait.) R. Br. (Asclepiadaceae) along with n-decanoyl-β-D-glucopyranoside 1, n-hexacosanoyl-β-D-glucopyranoside 2 and n-octadecanoyl-β-D-glucopyranoside 3. The spectral data of 4 and 5 have been given and structures are established.
Mittal,Ali
p. 641 - 645
(2013/07/04)

Novel fluorescent ceramide derivatives for probing ceramidase substrate specificity
Ceramidases are key regulators of cell fate. The biochemistry of different ceramidases and of their substrate ceramide appears to be complex, mainly due to specific biophysical characteristics at the water-membrane interface. In the present study, we describe the design and synthesis of a set of fluorescently labeled ceramides as substrates for acid and neutral ceramidases. For the first time we have replaced the commonly used polar NBD-dye with the lipophilic Nile Red (NR) dye. Analysis of kinetic data reveal that although both the dyes do not have any noticeable preference for the substitution at acyl or sphingosine (Sph) part in ceramide towards hydrolysis by acid ceramidase, the ceramides with acyl-substituted NBD and Sph-substituted NR dyes have been found to be a better substrate for neutral ceramidase.
Bhabak, Krishna P.,Proksch, Denny,Redmer, Susanne,Arenz, Christoph
p. 6154 - 6161
(2012/11/07)

Phospholipases a1 from armillaria ostoyae provide insight into the substrate recognition of a/b-hydrolase fold enzymes
Four enzymes with phospholipase A1(PLA1) activity were purified from the fruiting bodies of the basidiomycete Armillaria ostoyae. The enzymes (PLA1-1, -2, -3 and -4) showed similar isoelectric points (4.3, 3.9, 4.0 and 4.0) and apparent molecular masses in the range of 35-47 kDa. Mass spectrometric analyses of proteolytic fragments revealed sequences homologous to a/b-hydrolase fold enzymes. The enzymes share one conserved region with fungal phospholipases B and the active site sequence with bacterial esterases and PLA1s. PLA1-1 cleaves phospholipids and lysophospholipids with an optimum activity at pH 5.3. In contrast, PLA1-2, -3 and -4 are characterized by broad pH optima in the slightly acidic to neutral range and are additionally capable of hydrolyzing mono- and diglycerides as well as fatty acid methyl esters. All enzymes favor glycerol-based lipids with a single medium-sized fatty acid moiety in the sn-1 position but show reduced activity towards the corresponding 1, 2-diacyl derivatives with bulky long-chain or inflexible saturated fatty acid moieties in the sn-2 position. The enzymes prefer zwitterionic phospholipid substrates and are unable to hydrolyze triglycerides. From the selectivity of these broad-spectrum a/b-hydrolase fold enzymes towards the different classes of their substrates a regiospecific steric hindrance and a head group recognition are concluded.
Dippe, Martin,Mueller, Mathias Q.,Sinz, Andrea,Ulbrich-Hofmann, Renate
p. 1435 - 1448
(2012/10/29)

A thermoalkaliphilic halotolerant esterase from Rhodococcus sp. LKE-028 (MTCC 5562): Enzyme purification and characterization
A newly isolated Rhodococcus sp. LKE-028 (MTCC 5562) from soil samples of Gangotri region of Uttarakhand Himalayan produced a thermostable esterase. The enzyme was purified to homogeneity with purification fold 62.8 and specific activity 861.2 U mg-1 proteins along with 26.7% recovery. Molecular mass of the purified enzyme was 38 kDa and values of Km and V max were 525 nM and 1666.7 U mg-1 proteins, respectively. The esterase was active over a broad range of temperature (40-100 °C) and pH (7.0-12.0). The esterase was most active at pH 11.0. The optimum temperature of enzyme activity was 70°C and the enzyme was completely stable after 3 h pre-incubation at 60°C. Metal ions like Ca2+, Mg2+ and Co2+ stimulated enzyme activities. Purified esterase remarkably retained its activity with 10 M NaCl. Enzyme activity was slightly increased in presence of non-polar detergents (Tween 20, Tween 80 and Triton X 100), and compatible with oxidizing agents (H2O2) and reducing agents (β-mercaptoethanol). Activities of the enzyme was stimulated in presence of organic solvents like DMSO, benzene, toluene, methanol, ethyl alcohol, acetone, isoamyl alcohol after 10 days long incubation. The enzyme retained over 75% activity in presence of proteinase K. Besides hyperthermostability and halotolerancy the novelty of this enzyme is its resistance against protease.
Kumar, Lokendra,Singh, Balvinder,Adhikari, Dilip Kumar,Mukherjee, Joydeep,Ghosh, Debashish
experimental part
p. 983 - 991
(2012/08/28)

Deuterium kinetic isotope effects on the dissociation of a protein-fatty acid complex in the gas phase
Deuterium kinetic isotope effects (KIEs) are reported for the first time for the dissociation of a protein-ligand complex in the gas phase. Temperature-dependent rate constants were measured for the loss of neutral ligand from the deprotonated ions of the 1:1 complex of bovine β-lactoglobulin (Lg) and palmitic acid (PA), (Lg + PA)n- → Lgn- + PA, at the 6- and 7- charge states. At 25 °C, partial or complete deuteration of the acyl chain of PA results in a measurable inverse KIE for both charge states. The magnitude of the KIEs is temperature dependent, and Arrhenius analysis of the rate constants reveals that deuteration of PA results in a decrease in activation energy. In contrast, there is no measurable deuterium KIE for the dissociation of the (Lg + PA) complex in aqueous solution at pH 8. Deuterium KIEs were calculated using conventional transition-state theory with an assumption of a late dissociative transition state (TS), in which the ligand is free of the binding pocket. The vibrational frequencies of deuterated and non-deuterated PA in the gas phase and in various solvents (n-hexane, 1-chlorohexane, acetone, and water) were established computationally. The KIEs calculated from the corresponding differences in zero-point energies account qualitatively for the observation of an inverse KIE but do not account for the magnitude of the KIEs nor their temperature dependence. It is proposed that the dissociation of the (Lg + PA) complex in aqueous solution also proceeds through a late TS in which the acyl chain is extensively hydrated such that there is no significant differential change in the vibrational frequencies along the reaction coordinate and, consequently, no significant KIE.
Liu, Lan,Michelsen, Klaus,Kitova, Elena N.,Schnier, Paul D.,Brown, Alex,Klassen, John S.
supporting information; scheme or table
p. 5931 - 5937
(2012/05/07)

N,N-diarylammonium pyrosulfate as a highly effective reverse micelle-type catalyst for hydrolysis of esters
Reverse micelle-type N,N-diarylammonium pyrosulfate (3-5 mol %) efficiently catalyzes the hydrolysis of esters (up to 100 mmol scale) under organic solvent-free conditions. The present method is successfully applied to the hydrolysis of various esters without the decomposition of the base-sensitive moieties and without any loss of optical purity for α-heterosubstituted carboxylic acids.
Koshikari, Yoshiki,Sakakura, Akira,Ishihara, Kazuaki
supporting information; experimental part
p. 3194 - 3197
(2012/07/31)

Halimodendrin I, a new acylated triterpene glycoside from Halimodendron halodendron (Fabaceae)
Halimodendrin I, a new acylated triterpene glycoside (1), was isolated and chemically characterized as 3β-O-palmitoyl-28-[3′-palmitoyl-β-d- glucopyranosyl]-olean-12-en-28-oic acid from the aerial part of Halimodendron halodendron (Fabaceae) by IR, 1D and 2D NMR, HR-ESI-MS and LR-ESI-MS experiments. In addition, seven known compounds were isolated and identified as: palmitic acid, glycerol-2-linoleneate, glycerol-1,3-dilinoleneate, ferulic acid, 3-O-methylquercetin, β-sitosterol, and β-sitosterol-3-O-β- d-glucopyranoside. Nine fatty acids were identified and quantified in the saponifiable matter of the hexane extract. These fatty acids are: myristic, n-pentadecanoic, palmitoleic, palmitic, linoleic, oleic, stearic, arachidic, and behenic acids. The volatile oil was isolated by hydrodistillation (0.013%, w/w) with unpleasant smell. Twenty-seven components were identified in the oil by GC/MS.
Kozhamkulova, Zhanar A.,Radwan, Mohamed M.,Zhusupova, Galiya E.,Abilov, Zharilkasin A.,Ross, Samir A.
experimental part
p. 323 - 327
(2012/05/04)

Purification and characterization of OleA from Xanthomonas campestris and demonstration of a non-decarboxylative claisen condensation reaction
OleA catalyzes the condensation of fatty acyl groups in the first step of bacterial long-chain olefin biosynthesis, but the mechanism of the condensation reaction is controversial. In this study, OleA from Xanthomonas campestris was expressed in Escherichia coli and purified to homogeneity. The purified protein was shown to be active with fatty acyl-CoA substrates that ranged from C 8 to C16 in length. With limiting myristoyl-CoA (C 14), 1 mol of the free coenzyme A was released/mol of myristoyl-CoA consumed. Using [14C]myristoyl-CoA, the other products were identified as myristic acid, 2-myristoylmyristic acid, and 14-heptacosanone. 2-Myristoylmyristic acid was indicated to be the physiologically relevant product of OleA in several ways. First, 2-myristoylmyristic acid was the major condensed product in short incubations, but over time, it decreased with the concomitant increase of 14-heptacosanone. Second, synthetic 2-myristoylmyristic acid showed similar decarboxylation kinetics in the absence of OleA. Third, 2-myristoylmyristic acid was shown to be reactive with purified OleC and OleD to generate the olefin 14-heptacosene, a product seen in previous in vivo studies. The decarboxylation product, 14-heptacosanone, did not react with OleC and OleD to produce any demonstrable product. Substantial hydrolysis of fatty acyl-CoA substrates to the corresponding fatty acids was observed, but it is currently unclear if this occurs in vivo. In total, these data are consistent with OleA catalyzing a non-decarboxylative Claisen condensation reactionin the first step of the olefin biosynthetic pathway previously found to be presentin at least 70 different bacterial strains.
Frias, Janice A.,Richman, Jack E.,Erickson, Jasmine S.,Wackett, Lawrence P.
experimental part
p. 10930 - 10938
(2012/03/26)