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Squamins C–F, four cyclopeptides from the seeds of Annona globiflora
Four cyclic octapeptides, squamins C–F, were isolated from the seeds of Annona globiflora Schltdl. These compounds share part of their amino acid sequence, -Pro-Met(O)-Tyr-Gly-Thr-, with previously reported squamins A and B. Their structures were determined using NMR spectroscopic techniques together with quantum mechanical calculations (QM-NMR), ESI-HRMS data and a modified version of Marfey's chromatographic method. All compounds showed cytotoxic activity against DU-145 (human prostate cancer) and HeLa (human cervical carcinoma) cell lines. Clearly, A. globiflora is an important source of bioactive molecules, which could promote the sustainable exploitation of this undervalued specie.
Sosa-Rueda, Javier,Domínguez-Meléndez, Vanihamin,Ortiz-Celiseo, Araceli,López-Fentanes, Fernando C.,Cuadrado, Cristina,Fernández, José J.,Daranas, Antonio Hernández,Cen-Pacheco, Francisco
(2021/08/04)

Enhanced carboxypeptidase efficacies and differentiation of peptide epimers
Carboxypeptidases enzymatically cleave the peptide bond of C-terminal amino acids. In humans, it is involved in enzymatic synthesis and maturation of proteins and peptides. Carboxypeptidases A and Y have difficulty hydrolyzing the peptide bond of dipeptides and some other amino acid sequences. Early investigations into different N-blocking groups concluded that larger moieties increased substrate susceptibility to peptide bond hydrolysis with carboxypeptidases. This study conclusively demonstrates that 6-aminoquinoline-N-hydroxysuccimidyl carbamate (AQC) as an N-blocking group greatly enhances substrate hydrolysis with carboxypeptidase. AQC addition to the N-terminus of amino acids and peptides also improves chromatographic peak shapes and sensitivities via mass spectrometry detection. These enzymes have been used for amino acid sequence determination prior to the advent of modern proteomics. However, most modern proteomic methods assume that all peptides are comprised of L-amino acids and therefore cannot distinguish L-from D-amino acids within the peptide sequence. The majority of existing methods that allow for chiral differentiation either require synthetic standards or incur racemization in the process. This study highlights the resistance of D-amino acids within peptides to enzymatic hydrolysis by Carboxypeptidase Y. This stereoselectivity may be advantageous when screening for low abundance peptide stereoisomers.
Sung, Yu-Sheng,Putman, Joshua,Du, Siqi,Armstrong, Daniel W.
(2022/01/29)

Recreating the natural evolutionary trend in key microdomains provides an effective strategy for engineering of a thermomicrobial N-demethylase
N-demethylases have been reported to remove the methyl groups on primary or secondary amines, which could further affect the properties and functions of biomacromolecules or chemical compounds; however, the substrate scope and the robustness of N-demethylases have not been systematically investigated. Here we report the recreation of natural evolution in key microdomains of the Thermomicrobium roseum sarcosine oxidase (TrSOX), an N-demethylase with marked stability (melting temperature over 100 C) and enantioselectivity, for enhanced substrate scope and catalytic efficiency on -C-N-bonds. We obtained the structure of TrSOX by crystallization and X-ray diffraction (XRD) for the initial framework. The natural evolution in the nonconserved residues of key microdomains—including the catalytic loop, coenzyme pocket, substrate pocket, and entrance site—was then identified using ancestral sequence reconstruction (ASR), and the substitutions that accrued during natural evolution were recreated by site-directed mutagenesis. The single and double substitution variants catalyzed the N-demethylation of N-methyl-L-amino acids up to 1800- and 6000-fold faster than the wild type, respectively. Additionally, these single substitution variants catalyzed the terminal N-demethylation of non-amino-acid compounds and the oxidation of the main chain -C-N- bond to a -C=N- bond in the nitrogen-containing heterocycle. Notably, these variants retained the enantioselectivity and stability of the initial framework. We conclude that the variants of TrSOX are of great potential use in N-methyl enantiomer resolution, main-chain Schiff base synthesis, and alkaloid modification or degradation.
Gu, Zhenghua,Guo, Zitao,Shao, Jun,Shen, Chen,Shi, Yi,Tang, Mengwei,Xin, Yu,Zhang, Liang
(2022/03/09)

Electrochemical Synthesis of Glycine from Oxalic Acid and Nitrate
In manufacturing C?N bond-containing compounds, it is an important challenge to alternate the conventional methodologies that utilize reactive substrates, toxic reagents, and organic solvents. In this study, we developed an electrochemical method to synthesize a C?N bond-containing molecule avoiding the use of cyanides and amines by harnessing nitrate (NO3?) as a nitrogen source in an aqueous electrolyte. In addition, we utilized oxalic acid as a carbon source, which can be obtained from electrochemical conversion of CO2. Thus, our approach can provide a route for the utilization of anthropogenic CO2 and nitrate wastes, which cause serious environmental problems including global warming and eutrophication. Interestingly, the coreduction of oxalic acid and nitrate generated reactive intermediates, which led to C?N bond formation followed by further reduction to an amino acid, namely, glycine. By carefully controlling this multireduction process with a fabricated Cu–Hg electrode, we demonstrated the efficient production of glycine with a faradaic efficiency (F.E.) of up to 43.1 % at ?1.4 V vs. Ag/AgCl (current density≈90 mA cm?2).
Balamurugan, Mani,Choi, Seungwoo,Im, Sang Won,Jang, Jun Ho,Jo, Young In,Kim, Jeong Eun,Lee, Kyu Min,Lee, Moo Young,Nam, Ki Tae
supporting information
p. 21943 - 21951
(2021/08/30)

Enhancing the Catalytic Activity of MOF-808 Towards Peptide Bond Hydrolysis through Synthetic Modulations
The performance of MOFs in catalysis is largely derived from structural features, and much work has focused on introducing structural changes such as defects or ligand functionalisation to boost the reactivity of the MOF. However, the effects of different parameters chosen for the synthesis on the catalytic reactivity of the resulting MOF remains poorly understood. Here, we evaluate the role of metal precursor on the reactivity of Zr-based MOF-808 towards hydrolysis of the peptide bond in the glycylglycine model substrate. In addition, the effect of synthesis temperature and duration has been investigated. Surprisingly, the metal precursor was found to have a large influence on the reactivity of the MOF, surpassing the effect of particle size or number of defects. Additionally, we show that by careful selection of the Zr-salt precursor and temperature used in MOF syntheses, equally active MOF catalysts could be obtained after a 20 minute synthesis compared to 24 h synthesis.
Parac-Vogt, Tatjana N.,Simms, Charlotte,de Azambuja, Francisco
supporting information
p. 17230 - 17239
(2021/12/02)

Method for photolysis of amido bonds
The invention discloses a method for photo-splitting amido bonds, wherein the method is mild in reaction condition and can realize splitting of amido bonds by using illumination. The method for photo-splitting the amido bonds comprises the following steps: reacting 2,4-dinitrofluorobenzene with an amino group of a substance which contains alpha amino acid at the tail end and is shown as a structural formula I to generate a compound 1 represented by a structural formula II; and under light irradiation, carrying out amido bond cleavage reaction on the compound 1, wherein R1 is a side chain group of alpha-amino acid, and R2 is aryl, aliphatic hydrocarbon, -CH(R)-COOH or polypeptide.
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Paragraph 0046; 0048-0049; 0122-0125

(2021/06/26)

Powerful Steroid-Based Chiral Selector for High-Throughput Enantiomeric Separation of α-Amino Acids Utilizing Ion Mobility-Mass Spectrometry
Stereospecific recognition of amino acids (AAs) plays a crucial role in chiral biomarker-based diagnosis and prognosis. Separation of AA enantiomers is a long and tedious task due to the requirement of AA derivatization prior to the chromatographic or electrophoretic steps which are also time-consuming. Here, a mass-tagged chiral selector named [d0]/[d5]-estradiol-3-benzoate-17β-chloroformate ([d0]/[d5]-17β-EBC) with high reactivity and good enantiomeric resolution in regard to AAs was developed. After a quick and easy chemical derivatization step of AAs using 17β-EBC as the single chiral selector before ion mobility-mass spectrometry analysis, good enantiomer separation was achieved for 19 chiral proteinogenic AAs in a single analytical run (～2 s). A linear calibration curve of enantiomeric excess was also established using [d0]/[d5]-17β-EBC. It was demonstrated to be capable of determining enantiomeric ratios down to 0.5% in the nanomolar range. 17β-EBC was successfully applied to investigate the absolute configuration of AAs among peptide drugs and detect trace levels of-AAs in complex biological samples. These results indicated that [d0]/[d5]-17β-EBC may contribute to entail a valuable step forward in peptide drug quality control and discovering chiral disease biomarkers.
Li, Yuling,Zhou, Bowen,Wang, Keke,Zhang, Jing,Sun, Wenjian,Zhang, Li,Guo, Yinlong
p. 13589 - 13596
(2021/10/21)

Mechanistic insight into metal ion-catalyzed transamination
Several classes of biological reactions that are mediated by an enzyme and a co-factor can occur, to a slower extent, not only without the enzyme but even without the co-factor, under catalysis by metal ions. This observation has led to the proposal that metabolic pathways progressively evolved from using inorganic catalysts to using organocatalysts of increasing complexity. Transamination, the biological process by which ammonia is transferred between amino acids and α-keto acids, has a mechanism that has been well studied under enzyme/co-factor catalysis and under co-factor catalysis, but the metal ion-catalyzed variant was generally studied mostly at high temperatures (70-100 °C), and the details of its mechanism remained unclear. Here, we investigate which metal ions catalyze transamination under conditions relevant to biology (pH 7, 20-50 °C) and study the mechanism in detail. Cu2+, Ni2+, Co2+, and V5+ were identified as the most active metal ions under these constraints. Kinetic, stereochemical, and computational studies illuminate the mechanism of the reaction. Cu2+ and Co2+ are found to predominantly speed up the reaction by stabilizing a key imine intermediate. V5+ is found to accelerate the reaction by increasing the acidity of the bound imine. Ni2+ is found to do both to a limited extent. These results show that direct metal ion-catalyzed amino group transfer is highly favored even in the absence of co-factors or protein catalysts under biologically compatible reaction conditions.
Mayer, Robert J.,Kaur, Harpreet,Rauscher, Sophia A.,Moran, Joseph
supporting information
p. 19099 - 19111
(2021/11/22)

Mechanochemical Prebiotic Peptide Bond Formation**
The presence of amino acids on the prebiotic Earth, either stemming from endogenous chemical routes or delivered by meteorites, is consensually accepted. Prebiotically plausible pathways to peptides from inactivated amino acids are still unclear as most oligomerization approaches rely on thermodynamically disfavored reactions in solution. Now, a combination of prebiotically plausible minerals and mechanochemical activation enables the oligomerization of glycine at ambient temperature in the absence of water. Raising the reaction temperature increases the degree of oligomerization concomitantly with the formation of a commonly unwanted cyclic glycine dimer (DKP). However, DKP is a productive intermediate in the mechanochemical oligomerization of glycine. The findings of this research show that mechanochemical peptide bond formation is a dynamic process that provides alternative routes towards oligopeptides and establishes new synthetic approaches for prebiotic chemistry.
Cindro, Nikola,Grube?i?, Sa?a,Hernández, José G.,Me?trovi?, Ernest,Stolar, Tomislav,U?arevi?, Krunoslav
supporting information
p. 12727 - 12731
(2021/05/07)

Targeted Isolation of Asperheptatides from a Coral-Derived Fungus Using LC-MS/MS-Based Molecular Networking and Antitubercular Activities of Modified Cinnamate Derivatives
Under the guidance of MS/MS-based molecular networking, four new cycloheptapeptides, namely, asperheptatides A-D (1-4), were isolated together with three known analogues, asperversiamide A-C (5-7), from the coral-derived fungus Aspergillus versicolor. The planar structures of the two major compounds, asperheptatides A and B (1 and 2), were determined by comprehensive spectroscopic data analysis. The absolute configurations of the amino acid residues were determined by advanced Marfey's method. The two structurally related trace metabolites, asperheptatides C and D (3 and 4), were characterized by ESI-MS/MS fragmentation methods. A series of new derivatives (8-26) of asperversiamide A (5) were semisynthesized. The antitubercular activities of 1, 2, and 5-26 against Mycobacterium tuberculosis H37Ra were also evaluated. Compounds 9, 13, 23, and 24 showed moderate activities with MIC values of 12.5 μM, representing a potential new class of antitubercular agents.
Chao, Rong,Hou, Xue-Mei,Xu, Wei-Feng,Hai, Yang,Wei, Mei-Yan,Wang, Chang-Yun,Gu, Yu-Cheng,Shao, Chang-Lun
p. 11 - 19
(2021/01/14)

Scope and limitations of reductive amination catalyzed by half-sandwich iridium complexes under mild reaction conditions
The conversion of aldehydes and ketones to 1° amines could be promoted by half-sandwich iridium complexes using ammonium formate as both the nitrogen and hydride source. To optimize this method for green chemical synthesis, we tested various carbonyl substrates in common polar solvents at physiological temperature (37 °C) and ambient pressure. We found that in methanol, excellent selectivity for the amine over alcohol/amide products could be achieved for a broad assortment of carbonyl-containing compounds. In aqueous media, selective reduction of carbonyls to 1° amines was achieved in the absence of acids. Unfortunately, at Ir catalyst concentrations of 1 mM in water, reductive amination efficiency dropped significantly, which suggest that this catalytic methodology might be not suitable for aqueous applications where very low catalyst concentration is required (e.g., inside living cells).
Nguyen, Dat P.,Sladek, Rudolph N.,Do, Loi H.
supporting information

(2020/07/15)

Deactivation behavior and aggregation mechanism of supported Au nanoparticles in the oxidation of monoethanolamine to glycine
Deactivation behaviors of gold catalysts in the liquid-phase oxidation of monoethanolamine to glycine were revealed. Properties of the catalysts including Au loading, the valence distribution, and particle size of Au nanoparticles before and after batch reactions were investigated by BET, ICP, XRD, XPS, and TEM. It was found that the main reason for the catalytic deactivation was aggregation of Au nanoparticles. The Au aggregation mechanism of oxidative dissolution-reductive deposition in the reaction was proposed and this mechanism could help to understand the common aggregation of Au nanoparticles in the liquid-phase oxidation of alcohols.
Li, Zengxi,Meng, Xiangzhan,Wang, Hui,Yan, Ruiyi,Zhang, Yongqiang
(2020/08/07)

Studies on the synthesis and stability of α-ketoacyl peptides
Oxidative stress, an excess of reactive oxygen species (ROS), may lead to oxidative post-translational modifications of proteins resulting in the cleavage of the peptide backbone, known as α-amidation, and formation of fragments such as peptide amides and α-ketoacyl peptides (α-KaP). In this study, we first compared different approaches for the synthesis of different model α-KaP and then investigated their stability compared to the corresponding unmodified peptides. The stability of peptides was studied at room temperature or at temperatures relevant for food processing (100?°C for cooking and 150?°C as a simulation of roasting) in water, in 1% (m/v) acetic acid or as the dry substance (to simulate the thermal treatment of dehydration processes) by HPLC analysis. Oxidation of peptides by 2,5-di-tert-butyl-1,4-benzoquinone (DTBBQ) proved to be the most suited method for synthesis of α-KaPs. The acyl side chain of the carbonyl-terminal α-keto acid has a crucial impact on the stability of α-KaPs. This carbonyl group has a catalytic effect on the hydrolysis of the neighboring peptide bond, leading to the release of α-keto acids. Unmodified peptides were significantly more stable than the corresponding α-KaPs. The possibility of further degradation reactions was shown by the formation of Schiff bases from glyoxylic or pyruvic acids with glycine and proven through detection of transamination products and Strecker aldehydes of α-keto acids by HPLC–MS/MS. We propose here a mechanism for the decomposition of α-ketoacyl peptides.
Sajapin, Johann,Hellwig, Michael
p. 1425 - 1438
(2020/10/19)

Pagoamide A, a Cyclic Depsipeptide Isolated from a Cultured Marine Chlorophyte, Derbesia sp., Using MS/MS-Based Molecular Networking
A thiazole-containing cyclic depsipeptide with 11 amino acid residues, named pagoamide A (1), was isolated from laboratory cultures of a marine Chlorophyte, Derbesia sp. This green algal sample was collected from America Samoa, and pagoamide A was isolated using guidance by MS/MS-based molecular networking. Cultures were grown in a light- and temperature-controlled environment and harvested after several months of growth. The planar structure of pagoamide A (1) was characterized by detailed 1D and 2D NMR experiments along with MS and UV analysis. The absolute configurations of its amino acid residues were determined by advanced Marfey's analysis following chemical hydrolysis and hydrazinolysis reactions. Two of the residues in pagoamide A (1), phenylalanine and serine, each occurred twice in the molecule, once in the d- and once in the l-configuration. The biosynthetic origin of pagoamide A (1) was considered in light of other natural products investigations with coenocytic green algae.
Cottrell, Garrison W.,Fang, Fang,Gerwick, Lena,Gerwick, William H.,Glukhov, Evgenia,Guan, Huashi,Kim, Hyunwoo,Leao, Tiago,Li, Yueying,Mao, Huanru Henry,Murray, Thomas F.,Pierce, Marsha L.,Yu, Hao-Bing,Zhang, Chen,Zhang, Yi
supporting information

(2020/01/31)

PERMANENTLY POLARIZED HYDROXYAPATITE, A PROCESS FOR ITS MANUFACTURE AND USES THEREOF
The present invention relates to a permanently polarized hydroxyapatite and a composition or material comprising thereof. The present invention further relates to a process for obtaining a permanently polarized hydroxyapatite and to different uses of the permanently polarized hydroxyapatite or the composition or material comprising thereof.
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Paragraph 0191-0199

(2020/07/04)

Interplay between structural parameters and reactivity of Zr6-based MOFs as artificial proteases
Structural parameters influencing the reactivity of metal-organic frameworks (MOF) are challenging to establish. However, understanding their effect is crucial to further develop their catalytic potential. Here, we uncovered a correlation between reaction kinetics and the morphological structure of MOF-nanozymes using the hydrolysis of a dipeptide under physiological pH as model reaction. Comparison of the activation parameters in the presence of NU-1000 with those observed with MOF-808 revealed the reaction outcome is largely governed by the Zr6 cluster. Additionally, its structural environment completely changes the energy profile of the hydrolysis step, resulting in a higher energy barrier ΔG? for NU-1000 due to a much larger ΔS? term. The reactivity of NU-1000 towards a hen egg white lysozyme protein under physiological pH was also evaluated, and the results pointed to a selective cleavage at only 3 peptide bonds. This showcases the potential of Zr-MOFs to be developed into heterogeneous catalysts for non-enzymatic but selective transformation of biomolecules, which are crucial for many modern applications in biotechnology and proteomics.
De Azambuja, Francisco,De Vos, Dirk,Loosen, Alexandra,Moons, Jens,Parac-Vogt, Tatjana N.,Simms, Charlotte,Smolders, Simon
p. 6662 - 6669
(2020/07/23)

Robustness, Entrainment, and Hybridization in Dissipative Molecular Networks, and the Origin of Life
How simple chemical reactions self-assembled into complex, robust networks at the origin of life is unknown. This general problem-self-assembly of dissipative molecular networks-is also important in understanding the growth of complexity from simplicity in molecular and biomolecular systems. Here, we describe how heterogeneity in the composition of a small network of oscillatory organic reactions can sustain (rather than stop) these oscillations, when homogeneity in their composition does not. Specifically, multiple reactants in an amide-forming network sustain oscillation when the environment (here, the space velocity) changes, while homogeneous networks-those with fewer reactants-do not. Remarkably, a mixture of two reactants of different structure-neither of which produces oscillations individually-oscillates when combined. These results demonstrate that molecular heterogeneity present in mixtures of reactants can promote rather than suppress complex behaviors.
Cafferty, Brian J.,Wong, Albert S. Y.,Semenov, Sergey N.,Belding, Lee,Gmür, Samira,Huck, Wilhelm T. S.,Whitesides, George M.
supporting information
p. 8289 - 8295
(2019/06/04)

Stalobacin: Discovery of Novel Lipopeptide Antibiotics with Potent Antibacterial Activity against Multidrug-Resistant Bacteria
A novel lipopeptide antibiotic, stalobacin I (1), was discovered from a culture broth of an unidentified Gram-negative bacterium. Stalobacin I (1) had a unique chemical architecture composed of an upper and a lower half peptide sequence, which were linked via a hemiaminal methylene moiety. The sequence of 1 contained an unusual amino acid, carnosadine, 3,4-dihydroxyariginine, 3-hydroxyisoleucine, and 3-hydroxyaspartic acid, and a novel cyclopropyl fatty acid. The antibacterial activity of 1 against a broad range of drug-resistant Gram-positive bacteria was much stronger than those of last resort antibiotics such as vancomycin, linezolid, and telavancin (MIC 0.004-0.016 μg/mL). Furthermore, compound 1 induced a characteristic morphological change in Gram-positive and Gram-negative strains by inflating the bacterial cell body. The absolute configuration of a cyclopropyl amino acid, carnosadine, was determined by the synthetic study of its stereoisomers, which was an essential component for the strong activity of 1.
Matsui, Kouhei,Matsui, Kouhei,Kan, Yukiko,Kikuchi, Junko,Matsushima, Keisuke,Takemura, Miki,Maki, Hideki,Kozono, Iori,Ueda, Taichi,Minagawa, Kazuyuki
supporting information
p. 6090 - 6095
(2020/07/10)

Method for producing glycine (by machine translation)
The present invention relates to a method .for producing glycine comprising contacting the glycolic acid with an ammonia source with a catalyst, the catalyst comprising a carrier and at least one of the metal active components; selected from the group consisting; and Ru, Re, Rh, Pd, Pt, Co, Ni, Cu, Cr, Nb selected from the group consisting of elemental Ir and oxides thereof, or combinations, thereof. (by machine translation)
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Paragraph 0054-0143

(2020/05/01)

Nicotinamide riboside-amino acid conjugates that are stable to purine nucleoside phosphorylase
The nutraceutical Nicotinamide Riboside (NR), an efficacious biosynthetic precursor to NAD, is readily metabolized by the purine nucleoside phosphorylase (PNP). Access to the PNP-stable versions of NR is difficult because the glycosidic bond of NR is easily cleaved. Unlike NR, NRH, the reduced form of NR, offers sufficient chemical stability to allow the successful functionalisation of the ribosyl-moiety. Here, we report on a series of NRH and NR derived amino acid conjugates, generated in good to excellent yields and show that O5′-esterification prevents the PNP-catalyzed phosphorolysis of these NR prodrugs.
Hayat, Faisal,Migaud, Marie E.
supporting information
p. 2877 - 2885
(2020/04/28)

Method for continuous co-production of glycine and hydantoin
A method for continuous co-production of glycine and hydantoin is provided. The method includes subjecting an amino source, a carbon source, water and hydroxyacetonitrile to a hydantoin synthesizing reaction in a shell-and-tube reactor to obtain a first reaction product; feeding the first reaction product into a flash column for treatment to obtain a first treatment product; dividing the first treatment product into a first portion and a second portion; subjecting the first portion to first concentration treatment in an evaporator to obtain a first concentrate; reacting the first concentrate with concentrated sulfuric acid to obtain a second reaction product including hydantoin; subjecting the second portion to hydantoin decomposition in a tank series reactor to obtain a third reaction product including glycine. Compared with the prior art, the method realizes the continuous co-production of the glycine and the hydantoin.
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Paragraph 0047-0052

(2019/07/16)

Electrosynthesis of amino acids from biomass-derivable acids on titanium dioxide
Seven amino acids were electrochemically synthesized from biomass-derivable α-keto acids and NH2OH with faradaic efficiencies (FEs) of 77-99% using an earth-Abundant TiO2 catalyst. Furthermore, we newly constructed a flow-Type electrochemical reactor, named a "polymer electrolyte amino acid electrosynthesis cell", and achieved continuous production of alanine with an FE of 77%.
Fukushima, Takashi,Yamauchi, Miho
supporting information
p. 14721 - 14724
(2019/12/24)

Heterologous production of asperipin-2a: Proposal for sequential oxidative macrocyclization by a fungi-specific DUF3328 oxidase
Asperipin-2a is a ribosomally synthesized and post-translationally modified peptide isolated from Asperigillus flavus. Herein, we report the heterologous production of asperipin-2a and determination of its absolute structure. Notably, the characteristic bicyclic structure was likely constructed by a single oxidase containing the DUF3328 domain.
Ye, Ying,Ozaki, Taro,Umemura, Myco,Liu, Chengwei,Minami, Atsushi,Oikawa, Hideaki
supporting information
p. 39 - 43
(2019/01/04)

Discovery of Amantamide, a Selective CXCR7 Agonist from Marine Cyanobacteria
CXCR7 plays an emerging role in several physiological processes. A linear peptide, amantamide (1), was isolated from marine cyanobacteria, and the structure was determined by NMR and mass spectrometry. The total synthesis was achieved by solid-phase method. After screening two biological target libraries, 1 was identified as a selective CXCR7 agonist. The selective activation of CXCR7 by 1 could provide the basis for developing CXCR7-targeted therapeutics and deciphering the role of CXCR7 in different diseases.
Liang, Xiao,Luo, Danmeng,Yan, Jia-Lei,Rezaei, Mohammad A.,Salvador-Reyes, Lilibeth A.,Gunasekera, Sarath P.,Li, Chenglong,Ye, Tao,Paul, Valerie J.,Luesch, Hendrik
supporting information
p. 1622 - 1626
(2019/03/07)

METHOD FOR PRODUCING alpha-AMINO ACID
The present invention relates to a method for producing a specified α-amino acid, the method including allowing a specified α-amino acid amide and water to react with each other in the presence of a zirconium compound which contains zirconium and at least one metal element selected from the group consisting of lithium, nickel, copper, zinc, cesium, barium, hafnium, tantalum, cerium, and dysprosium.
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Paragraph 0157-0158; 0160

(2019/06/24)

A New Microbial Pathway for Organophosphonate Degradation Catalyzed by Two Previously Misannotated Non-Heme-Iron Oxygenases
The assignment of biochemical functions to hypothetical proteins is challenged by functional diversification within many protein structural superfamilies. This diversification, which is particularly common for metalloenzymes, renders functional annotations that are founded solely on sequence and domain similarities unreliable and often erroneous. Definitive biochemical characterization to delineate functional subgroups within these superfamilies will aid in improving bioinformatic approaches for functional annotation. We describe here the structural and functional characterization of two non-heme-iron oxygenases, TmpA and TmpB, which are encoded by a genomically clustered pair of genes found in more than 350 species of bacteria. TmpA and TmpB are functional homologues of a pair of enzymes (PhnY and PhnZ) that degrade 2-aminoethylphosphonate but instead act on its naturally occurring, quaternary ammonium analogue, 2-(trimethylammonio)ethylphosphonate (TMAEP). TmpA, an iron(II)- and 2-(oxo)glutarate-dependent oxygenase misannotated as a γ-butyrobetaine (γbb) hydroxylase, shows no activity toward γbb but efficiently hydroxylates TMAEP. The product, (R)-1-hydroxy-2-(trimethylammonio)ethylphosphonate [(R)-OH-TMAEP], then serves as the substrate for the second enzyme, TmpB. By contrast to its purported phosphohydrolytic activity, TmpB is an HD-domain oxygenase that uses a mixed-valent diiron cofactor to enact oxidative cleavage of the C-P bond of its substrate, yielding glycine betaine and phosphate. The high specificities of TmpA and TmpB for their N-trimethylated substrates suggest that they have evolved specifically to degrade TMAEP, which was not previously known to be subject to microbial catabolism. This study thus adds to the growing list of known pathways through which microbes break down organophosphonates to harvest phosphorus, carbon, and nitrogen in nutrient-limited niches.
Rajakovich, Lauren J.,Pandelia, Maria-Eirini,Mitchell, Andrew J.,Chang, Wei-Chen,Zhang, Bo,Boal, Amie K.,Krebs, Carsten,Bollinger, J. Martin
p. 1627 - 1647
(2019/03/19)

Selective oxidation of monoethanolamine to glycine over supported gold catalysts: The influence of support and the promoting effect of polyvinyl alcohol
Glycine is an important fine chemical used in many fields, and the traditional synthetic methods like Strecker synthesis and ammoniation of chloroacetic acid use highly toxic reagents or produce equal molar byproducts. Herein, selective aerobic oxidation of monoethanolamine (MEA) to glycine using Au catalysts supported on various supports, including Al2O3, SiO2, TiO2, ZnO, and ZrO2, was investigated and the correlation between acid-base properties of the catalysts and catalytic performance was established. Catalysts with higher base content exhibited higher initial activity and that with lower acid content gave higher glycine selectivity. The influence of preparation methods was revealed using Au/ZrO2 with the best catalytic performance and it was demonstrated that the presence of polyvinyl alcohol (PVA) has a significant promoting effect. In-situ FTIR and 1H NMR analysis revealed that the hydrogen bonds between PVA and MEA can enhance adsorption of MEA on catalysts, resulting in doubled turnover frequency (TOF) and improved MEA conversion; and the preferential hydrogen bonds between the amino group of MEA and the hydroxyl of PVA can prevent the coordination of amino group with Au nanoparticles, favoring reaction of the hydroxyl group of MEA on the active sites, accounting for the enhanced glycine selectivity. The reaction conditions were optimized and the optimal yield of glycine was 95%.
Meng, Xiangzhan,Bai, Yinge,Xu, Haiyang,Zhang, Yongqiang,Li, Chunshan,Wang, Hui,Li, Zengxi
p. 131 - 143
(2019/03/26)

High efficiency production method of glycine
The invention discloses a high efficiency production method of glycine. The high efficiency production method comprises following steps: solvent methanol or ethanol, and catalyst urotropine or paraformaldehyde are introduced into a reactor, Ammonium-monochloracetat is added, the temperature is increased to 60 to 70 DEG C, N,N-Diisopropylethylamine or N,N-Diethylbenzylamine or N, N-di-n-propyl benzylamine or N, N-di-n-butyl benzylamine are added dropwise in 2h, thermal insulation reaction is carried out at 65 to 75 DEG C for 2.5h, the temperature is reduced to 40 to 50 DEG C for precipitation of glycine crystal, or the temperature is reduced to 10 to 25 DEG C for precipitation of a mixture of glycine crystal and an ammonium salt; and then filtering, washing, and drying are carried out successively so as to obtain a glycine product, wherein a washing liquid is adopted for recycling of N,N-Diisopropylethylamine or N,N-Diethylbenzylamine or N, N-di-n-propyl benzylamine or N, N-di-n-butyl benzylamine. The glycine yield is increased by 10% of that in the prior art; energy consumption is reduced; catalyst recycling is realized; recycling of N,N-Diisopropylethylamine or N,N-Diethylbenzylamine or N, N-di-n-propyl benzylamine or N, N-di-n-butyl benzylamine is realized; and combined production of ammonium chloride is realized.
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Paragraph 0038; 0039

(2018/06/26)

A homogeneous system in the method of catalytic synthesis of glycine (by machine translation)
The invention discloses a homogeneous system in the method of catalytic synthesis of glycine, to chloroacetic acid, ammonia gas as the raw material, in the substituted pyridines catalyst and the presence of a solvent under the situation of the aminolysis reaction, aminolysis reaction to obtain a reaction solution of filtering, washing after the operations to respectively obtain the glycine and ammonium chloride, the method of the invention, the reaction system of the precipitating and a homogeneous system to substituted pyridine as catalyst, which can effectively solve the hexamine catalytic efficiency is not high, the loss of catalyst, serious problems such as side reaction, has high conversion rate, the product is easy to purify, catalyst without loss and can be recycled and the like, the production cost is reduced, reducing the pollution, it has very high practical value. (by machine translation)
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Page/Page column 6-9

(2018/10/19)

The opposite effect of K+ and Na+ on the hydrolysis of linear and cyclic dipeptides
Potassium and sodium are generally considered inert ‘spectator’ ions for organic reactions. Here, we report rate constants for the acid-promoted hydrolysis of the seven dipeptides of glycine (G) and alanine (A) and an unexpected pattern in how these rates differ in the presence of K+ and Na+. The linear dipeptides hydrolyze 12–18% percent slower in the presence of KCl versus an equal concentration of NaCl, while the cyclic dipeptides hydrolyze 5–13% faster in the presence of KCl (all P-values + and others in Na+. The results offer a potential reason for life's mysterious universal selection of intracellular potassium over sodium.
Campbell, Thomas D.,Hart, Clara A.,Febrian, Rio,Cheneler, Mark L.,Bracher, Paul J.
supporting information
p. 2264 - 2267
(2018/05/23)

Water proton NMR detection of amide hydrolysis and diglycine dimerization
The transverse relaxation rate of water protons R2(1H2O) is found to be sensitive to amide hydrolysis and diglycine dimerization. The results demonstrate the feasibility of using R2(1H2O) as a diagnostic tool to detect chemical changes in aqueous solutions. Potential applications include drug product formulation and inspection.
Briggs, Katharine T.,Taraban, Marc B.,Bruce Yu
p. 7003 - 7006
(2018/07/05)

Design, synthesis, and conformational analysis of 3-: Cyclo -butylcarbamoyl hydantoins as novel hydrogen bond driven universal peptidomimetics
A collection of systematically substituted 3-cyclo-butylcarbamoyl hydantoins was synthesized by a regioselective multicomponent domino process followed by easy coupling reactions. Calculations, NMR studies and X-ray analysis show that these scaffolds are able to project their side chains similar to common secondary structures, such as the α-helix and β-turn, with favourable enthalpic and entropic profiles.
Bellucci,Frigerio,Castellano,Meneghetti,Sacchetti,Volonterio
supporting information
p. 521 - 525
(2018/02/07)

Sustainable synthesis of amino acids by catalytic fixation of molecular dinitrogen and carbon dioxide
The industrial process of nitrogen fixation is complex and results in a huge economic and environmental impact. It requires a catalyst and high temperature and pressure to induce the rupture of the strong N-N bond and subsequent hydrogenation. On the other hand, carbon dioxide removal from the atmosphere has become a priority objective due to the high amount of global carbon dioxide emissions (i.e. 36 200 million tons in 2015). In this work, we fix nitrogen from N2 and carbon from CO2 and CH4 to obtain both glycine and alanine (d/l racemic mixture), the two simplest amino acids. The synthesis, catalyzed by polarized hydroxyapatite under UV light irradiation and conducted in an inert reaction chamber, starts from a simple gas mixture containing N2, CO2, CH4 and H2O and uses mild reaction conditions. At atmospheric pressure and 95 °C, the glycine and alanine molar yields with respect to CH4 or CO2 are about 1.9% and 1.6%, respectively, but they grow to 3.4% and 2.4%, when the pressure increases to 6 bar and the temperature is maintained at 95 °C. Besides, the minimum temperature required for the successful production of detectable amounts of amino acids is 75 °C. Accordingly, an artificial photosynthetic process has been developed by using an electrophotocatalyst based on hydroxyapatite thermally and electrically stimulated and coated with zirconyl chloride and a phosphonate. The synthesis of amino acids by direct fixation of nitrogen and carbon from gas mixtures opens new avenues regarding the nitrogen fixation for industrial purposes and the recycling of carbon dioxide.
Rivas, Manuel,Del Valle, Luís J.,Turon, Pau,Alemán, Carlos,Puiggalí, Jordi
supporting information
p. 685 - 693
(2018/02/14)

Photolytic release of bioactive carboxylic acids from fused pyran conjugates
New ester cages bearing the coumarin (2H-benzopyran-2-one) skeleton with extended π-systems as phototriggers, for glycine and β-alanine, as models of carboxylic acid bifunctional molecules with biological relevance, were evaluated under photolysis conditions at 254, 300, 350 and 419 nm of irradiation in a RPR-100 photochemical reactor. The processes were followed by HPLC-UV detection and 1H NMR with collection of kinetic data. The results showed a correlation between the photolysis efficiency and the increasing extension of the conjugation for both glycine and β-alanine, showing that the 7-aminocoumarin afforded the best results at all wavelengths tested. From a study of the time-resolved fluorescence behaviour, these compounds were also found to exhibit more complex fluorescence decay kinetics. This was attributed to the presence of conjugated and non-conjugated coumarin species.
Concei??o, Rafaela,Hungerford, Graham,Costa, Susana P.G.,Gon?alves, M. Sameiro T.
p. 368 - 379
(2017/09/26)

Superactivity of MOF-808 toward Peptide Bond Hydrolysis
MOF-808, a Zr(IV)-based metal-organic framework, has been proven to be a very effective heterogeneous catalyst for the hydrolysis of the peptide bond in a wide range of peptides and in hen egg white lysozyme protein. The kinetic experiments with a series of Gly-X dipeptides with varying nature of amino acid side chain have shown that MOF-808 exhibits selectivity depending on the size and chemical nature of the X side chain. Dipeptides with smaller or hydrophilic residues were hydrolyzed faster than those with bulky and hydrophobic residues that lack electron rich functionalities which could engage in favorable intermolecular interactions with the btc linkers. Detailed kinetic studies performed by 1H NMR spectroscopy revealed that the rate of glycylglycine (Gly-Gly) hydrolysis at pD 7.4 and 60 °C was 2.69 × 10-4 s-1 (t1/2 = 0.72 h), which is more than 4 orders of magnitude faster compared to the uncatalyzed reaction. Importantly, MOF-808 can be recycled several times without significantly compromising the catalytic activity. A detailed quantum-chemical study combined with experimental data allowed to unravel the role of the {Zr6O8} core of MOF-808 in accelerating Gly-Gly hydrolysis. A mechanism for the hydrolysis of Gly-Gly by MOF-808 is proposed in which Gly-Gly binds to two Zr(IV) centers of the {Zr6O8} core via the oxygen atom of the amide group and the N-terminus. The activity of MOF-808 was also demonstrated toward the hydrolysis of hen egg white lysozyme, a protein consisting of 129 amino acids. Selective fragmentation of the protein was observed with 55% yield after 25 h under physiological pH.
Ly, Hong Giang T.,Fu, Guangxia,Kondinski, Aleksandar,Bueken, Bart,De Vos, Dirk,Parac-Vogt, Tatjana N.
p. 6325 - 6335
(2018/05/14)

Synthesis of Deuterated or Tritiated Glycine and Its Methyl Ester
Abstract: Heating glycine (Gly) and methyl glycinate (GlyOCH3) supported on 5% Pd/C or 5% Pt/C in a deuterium or tritium gas atmosphere gave the isotope-labeled products. The experiments were carried out at 180°C for 10 min. The deuterium atom inclusion under these conditions averaged up to 1.8 atoms per molecule for Gly and up to 1.0 atom per molecule for GlyOCH3. The reaction with tritium gas gave labeled products with a specific radioactivity of 27–31 Ci/mmol for Gly and 18 Ci/mmol for GlyOCH3.
Shevchenko,Andreeva,Nagaev, I. Yu.,Myasoedov
p. 266 - 267
(2019/01/03)

A colourful azulene-based protecting group for carboxylic acids
An intensely blue-coloured protecting group for carboxylic acids has been developed. The protecting group is introduced through a Steglich esterification that couples 6-(2-hydroxyethyl)azulene (AzulE) and the carboxylic acid substrate. Deprotection is effected under basic conditions by the addition of the amidine base DBU, whereupon cleavage occurs, accompanied by a colour change. A two-step deprotection methodology comprising activation with oxalyl chloride and deprotection with a very mild base was developed for use with base-sensitive substrates. The AzulE esters were found to be compatible with other commonly employed protecting groups – silyl ethers, MOM acetals – by studying their orthogonal and concomitant deprotections. The stability of the new protecting group towards various synthetic processes – oxidation, reduction, cross-coupling, olefination and treatment with base – provided the basis of a versatility profile. This indicated that AzulE esters are sensitive to strongly oxidising and basic agents while being compatible with reducing conditions and selected other reactions. The convenience of a highly coloured protecting group for tracking material (and avoiding loss of compound) through laboratory processes warrants further investigation of this and/or related species.
Bevan, Thomas W.,Francis-Taylor, James,Wong, Helena,Northcote, Peter T.,Harvey, Joanne E.
supporting information
p. 2942 - 2955
(2018/05/16)

Croissamide, a proline-rich cyclic peptide with an N-prenylated tryptophan from a marine cyanobacterium Symploca sp.
Croissamide, a proline-rich cyclic peptide that contains an N-prenylated tryptophan, was isolated from a marine cyanobacterium Symploca sp. Its gross structure was determined by spectroscopic analyses, and the absolute configuration was established based on chiral HPLC analyses of acid hydrolysates.
Iwasaki, Keitaro,Iwasaki, Arihiro,Sumimoto, Shimpei,Sano, Takuya,Hitomi, Yuki,Ohno, Osamu,Suenaga, Kiyotake
supporting information
p. 3806 - 3809
(2018/09/17)

Cyclic allylic carbonates as a renewable platform for protecting chemistry in water
The present work explores different cyclic allylic carbonates as a potential class of allylcarbamate precursors. The 5-membered carbonate formed a carbamate with very good thermal and pH stability, which could be cleanly deprotected in aqueous solution, in just 30 min with 2 mol% Pd(OAc)2 as catalyst. The polar nature of the installed motif made it possible to deprotect highly unpolar substrates in water as solvent.
Olsén, Peter,Morvan, Jennifer,Sawadjoon, Supaporn,Shatskiy, Andrey,Johnston, Eric V.,?kermark, Bj?rn
supporting information
p. 3186 - 3190
(2018/07/29)

Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry
It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have s
Mattia Bizzarri, Bruno,Botta, Lorenzo,Pérez-Valverde, Maritza Iveth,Saladino, Raffaele,Di Mauro, Ernesto,García-Ruiz, Juan Manuel
p. 8126 - 8132
(2018/05/29)

Method for synthesizing glycine under catalytic actions of ionic liquid in homogeneous system
The invention relates to a method for synthesizing glycine under catalytic actions of an ionic liquid in a homogeneous system. The method particularly comprises the following steps: performing ammonolysis reaction on chloroacetic acid and ammonia gas (or ammonia water or ammonium bicarbonate) used as reaction raw materials by using an ionic liquid as a catalyst to generate a glycine crude product, and performing recrystallization to obtain the glycine pure product. The method is simple to operate, has the advantages of recyclable catalyst and separable product, can easily implement industrial production, and provides effective solutions for the problems of high decomposability of the catalyst urotropine, low activity, severe side reaction, difficulty in recovery and the like in glycine synthesis.
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Paragraph 0014; 0015; 0017; 0019; 0021; 0023; 0025

(2017/10/13)

Nodupetide, a potent insecticide and antimicrobial from Nodulisporium sp. associated with Riptortus pedestris
Nodupetide (1), a new cyclodepsipeptide unique in its incorporation of a 3-hydroxy-4-methylhexanoic acid (HMHA) derived motif, was discovered from Nodulisporium sp. IFB-A163, a fungus residing in the insect (Riptortus pedestris) gut. The nodupetide structure was elucidated by its MS/MS and 2D NMR spectra, and its absolute configuration by the X-ray crystallography and modified Marfey's method. Nodupetide is insecticidal against rice brown planthopper (Nilaparvata lugens) with an LD50value of 70?ng/larva, and inhibitory towards the drug-resistant human pathogenic bacterium Pseudomonas aeruginosa with its MIC value (5.0?μM) comparable to that (3.2?μM) of ciprofloxacin, a prescribed antibacterial agent co-assayed equally.
Wu, Hui Min,Lin, Li Ping,Xu, Qin Lan,Han, Wen Bo,Zhang, Song,Liu, Ze Wen,Mei, Ya Ning,Yao, Zhu Jun,Tan, Ren Xiang
supporting information
p. 663 - 665
(2017/01/25)

Dudawalamides A-D, Antiparasitic Cyclic Depsipeptides from the Marine Cyanobacterium Moorea producens
A family of 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya)-containing cyclic depsipeptides, named dudawalamides A-D (1-4), was isolated from a Papua New Guinean field collection of the cyanobacterium Moorea producens using bioassay-guided and spectroscopic approaches. The planar structures of dudawalamides A-D were determined by a combination of 1D and 2D NMR experiments and MS analysis, whereas the absolute configurations were determined by X-ray crystallography, modified Marfey's analysis, chiral-phase GCMS, and chiral-phase HPLC. Dudawalamides A-D possess a broad spectrum of antiparasitic activity with minimal mammalian cell cytotoxicity. Comparative analysis of the Dhoya-containing class of lipopeptides reveals intriguing structure-activity relationship features of these NRPS-PKS-derived metabolites and their derivatives.
Almaliti, Jehad,Malloy, Karla L.,Glukhov, Evgenia,Spadafora, Carmenza,Gutiérrez, Marcelino,Gerwick, William H.
p. 1827 - 1836
(2017/06/28)

Purification, structural characterization and bioactivity evaluation of a novel proteoglycan produced by Corbicula fluminea
A novel proteoglycan, named CFPS-11, was isolated from Corbicula fluminea, which is a food source of freshwater bivalve mollusk. CFPS-11 had an average molecular weight of 807.7 kDa and consisted of D-glucose and D-glucosamine in a molar ratio of 12.2:1.0. The protein moiety (～5%) of CFPS-11 was covalently bonded to the polysaccharide chain in O-linkage type through both serine and thereonine residues. The polysaccharide chain of CFPS-11 was composed of (1 → 4)-α-D-glucopyranosyl and (1 → 3,6)-α-D-glucopyranosyl residues, which branched at O-6. The branch chain consisted of (1 →)-α-D-glucopyranosyl and (1 →)-α-D-N-acetylglucosamine residues. CFPS-11 exhibited significant antioxidant activity in a dose-dependent manner and remarkable inhibition activities against α-amylase and α-glucosidase by in vitro assays. These findings indicated that the CFPS-11 from C. fluminea has the potential for development as a health food ingredient.
Yan, Jing-Kun,Wang, Yao-Yao,Qiu, Wen-Yi,Wu, Li-Xia,Ding, Zhi-Chao,Cai, Wu-Dan
p. 11 - 18
(2017/08/29)

Process for preparing hyperpolarized substrates and method for MRI
The present invention generally relates to a process for the preparation of aqueous solutions of hyperpolarized molecules ready for use in in-vivo MR diagnostic imaging, the use thereof as MRI contrast agent in investigation methods for producing diagnostic MR images of a human or non-human animal body organ, region or tissue.
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Page/Page column 33; 34

(2017/08/01)

A new d-threonine aldolase as a promising biocatalyst for highly stereoselective preparation of chiral aromatic β-hydroxy-α-amino acids
d-Threonine aldolase is an enzyme belonging to the glycine-dependent aldolases, and it catalyzes the reversible aldol reaction of glycine and acetaldehyde to give d-threonine and/or d-allo-threonine. In this study, a putative d-threonine aldolase gene from Delftia sp. RIT313 was cloned and expressed in Escherichia coli BL21 (DE3). The purified enzyme (DrDTA, 47 KDa) exhibited 21.3 U mg-1 activity for the aldol addition of glycine and acetaldehyde in MES-NaOH buffer (pH 6.0) at 50 °C. Both pyridoxal 5′-phosphate and metal ions were needed for the reaction, and the existence of the metal ions enhanced the stability of the enzyme. It was found that the conversion and Cβ-stereoselectivity were dramatically influenced by the reaction temperature, co-solvent, amount of enzyme and reaction time, and it is possible to enable the reaction under kinetic control to retain suitable conversion and high stereoselectivity at the β-carbon, thus tackling the "Cβ-stereoselectivity problem". DrDTA showed high activity toward aromatic aldehydes with electron-withdrawing substituents. Under the optimized reaction conditions, phenylserines with a 2′-fluoro- or 3′-nitro-substituent were obtained with >90% conversion and >90% de. In addition, dl-threo-phenylserine and dl-threo-4-(methylsulfonyl)phenylserine were efficiently resolved with an excellent enantiomeric excess value (ee, >99%) using a whole cell biocatalyst in a two-phase system at 1.0 M and 0.3 M, respectively, the highest substrate concentration reported so far. These results suggested that DrDTA might be a promising biocatalyst for producing chiral aromatic β-hydroxy-α-amino acids.
Chen, Qijia,Chen, Xi,Cui, Yunfeng,Ren, Jie,Lu, Wei,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
p. 5964 - 5973
(2017/12/26)

Peroxymonosulfate activation by Mn3O4/metal-organic framework for degradation of refractory aqueous organic pollutant rhodamine B
An environmentally friendly Mn-oxide-supported metal-organic framework (MOF), Mn3O4/ZIF-8, was successfully prepared using a facile solvothermal method, with a formation mechanism proposed. The composite was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron microscopy, and Fourier-transform infrared spectroscopy. After characterization, the MOF was used to activate peroxymonosulfate (PMS) for degradation of the refractory pollutant rhodamine B (RhB) in water. The composite prepared at a 0.5:1 mass ratio of Mn3O4 to ZIF-8 possessed the highest catalytic activity with negligible Mn leaching. The maximum RhB degradation of approximately 98% was achieved at 0.4 g/L 0.5-Mn/ZIF-120, 0.3 g/L PMS, and 10 mg/L initial RhB concentration at a reaction temperature of 23 °C. The RhB degradation followed first-order kinetics and was accelerated with increased 0.5-Mn/ZIF-120 and PMS dosages, decreased initial RhB concentration, and increased reaction temperature. Moreover, quenching tests indicated that ?OH was the predominant radical involved in the RhB degradation; the ?OH mainly originated from SO4?? and, hence, PMS. Mn3O4/ZIF-8 also displayed good reusability for RhB degradation in the presence of PMS over five runs, with a RhB degradation efficiency of more than 96% and Mn leaching of less than 5% for each run. Based on these findings, a RhB degradation mechanism was proposed.
Hu, Longxing,Deng, Guihua,Lu, Wencong,Lu, Yongsheng,Zhang, Yuyao
p. 1360 - 1372
(2017/08/22)

Efficient Enzymatic Preparation of13N-Labelled Amino Acids: Towards Multipurpose Synthetic Systems
Nitrogen-13 can be efficiently produced in biomedical cyclotrons in different chemical forms, and its stable isotopes are present in the majority of biologically active molecules. Hence, it may constitute a convenient alternative to Fluorine-18 and Carbon-11 for the preparation of positron-emitter-labelled radiotracers; however, its short half-life demands for the development of simple, fast, and efficient synthetic processes. Herein, we report the one-pot, enzymatic and non-carrier-added synthesis of the13N-labelled amino acids l-[13N]alanine, [13N]glycine, and l-[13N]serine by using l-alanine dehydrogenase from Bacillus subtilis, an enzyme that catalyses the reductive amination of α-keto acids by using nicotinamide adenine dinucleotide (NADH) as the redox cofactor and ammonia as the amine source. The integration of both l-alanine dehydrogenase and formate dehydrogenase from Candida boidinii in the same reaction vessel to facilitate the in situ regeneration of NADH during the radiochemical synthesis of the amino acids allowed a 50-fold decrease in the concentration of the cofactor without compromising reaction yields. After optimization of the experimental conditions, radiochemical yields were sufficient to carry out in vivo imaging studies in small rodents.
da Silva, Eunice S.,Gómez-Vallejo, Vanessa,Baz, Zuri?e,Llop, Jordi,López-Gallego, Fernando
p. 13619 - 13626
(2016/09/13)

Environment-friendly production process for continuously synthesizing amino acetic acid
The invention discloses an environment-friendly production process for continuously synthesizing amino acetic acid and relates to the field of production of chemical raw materials. The environment-friendly production process comprises the following steps: adding chloroacetic acid into a three-necked bottle; when stirring, slowly dropwise adding a water solution of ammonium bicarbonate for neutralizing; adding a water solution of urea; heating and refluxing; naturally cooling and standing for 12h to 16h; carrying out alcohol precipitation with ethanol and filtering to obtain white crystals; dissolving the white crystals into a 3mol/L hydrochloric acid solution and heating and hydrolyzing for 3h; when stirring, slowly spraying 100mL of the ethanol; after continually stirring for 0.8h, filtering and washing; drying to obtain a target crude product; dissolving the crude product into water; when stirring, slowing spraying the ethanol and filtering to obtain crystals; washing the crystals with the ethanol for 2 to 5 times; drying the crystals to obtain a finished product; calculating the purity of the product and the yield of the product. The environment-friendly production process for continuously synthesizing the amino acetic acid, disclosed by the invention, is simple in process and convenient to operate; raw materials and reaction conditions are easy to obtain and the loss of ammonia is reduced; a catalyst urotropin is convenient to recycle.
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Paragraph 0012

(2017/02/09)

A cycle the reaction kettle method of producing glycine environmental protection law
The present invention relates to a method of production of glycine by a circulation environmental-friendly method in a reactor, comprising: adding methanol, chloroacetic acid and hexamine to the reactor, feeding ammonia to the reactor, reacting under a cooling condition, and centrifuging the reaction solution after the reaction is completed to obtain a glycine and ammonium chloride crystalline mixture solid and a mother liquor, wherein glycine and ammonium chloride are isolated from the solid, and the mother liquor is used as a raw material for a next reaction. The method is characterized in that: the reaction proceeds in the reactor, the volume of the reactor is greater than or equal to 5 cubic meters, the reactor is under the cooling and stirring condition, the speed of feeding ammonia to the reactor is controlled at the moles of ammonia per hour introduced into the reactor having a molar ratio of 0.5-2.0 with original chloroacetic acid in the reactor. The method of the present invention breaks through the technical problems of expansion production of glycine in methanol phase, and helps to achieve coordination of reaction rate and reaction time of the reaction system, so that the reaction process does not generate by-products, and the reaction rate is increased.
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Paragraph 0117-0119

(2017/01/09)