100-02-7Relevant articles and documents
Catalytic degradation of an organophosphorus agent at Zn-OH sites in a metal-organic framework
Mian, Mohammad Rasel,Islamoglu, Timur,Afrin, Unjila,Goswami, Subhadip,Cao, Ran,Kirlikovali, Kent O.,Hall, Morgan G.,Peterson, Gregory W.,Farha, Omar K.
, p. 6998 - 7004 (2020)
Chemical warfare agents (CWAs), and in particular organophosphorus nerve agents, still pose a significant threat to society due to their continued use despite international bans. While nature has constructed a variety of enzymes that are capable of rapidly hydrolyzing organophosphorus substrates, the poor stability of enzymes outside of buffered solutions has limited their use in practical applications, such as in filters or on protective suits. As a result, we have explored the use of metal-organic frameworks (MOFs) as robust and tunable catalytic materials in which the nodes can be tailored to resemble the active sites found in these enzymes. We identified the Zn-based MOF, MFU-4l, as a promising hydrolysis catalyst due to the presence of Zn(II)-OH groups on the nodes, which are structurally reminiscent of the active sites in carbonic anhydrase (CA), a Zn-based enzyme that has been shown to efficiently catalyze the hydrolysis of phosphate esters. Indeed, MFU-4l can rapidly hydrolyze both the organophosphorus nerve agent, GD, and its simulant, DMNP, with half-lives as low as 1 min, which is competitive with the some of best heterogeneous hydrolysis catalysts reported to date.
Biomimicking, metal-chelating and surface-imprinted polymers for the degradation of pesticides
Erdem, Murat,Say, Ridvan,Ers?z, Arzu,Denizli, Adil,Türk, Hayrettin
, p. 238 - 243 (2010)
Molecularly imprinted polymer beads (PIBs) and non-imprinted (control) polymer beads (NIBs) have been prepared from methacryloylhistidine-Co2+, -Ni2+, and -Zn2+ monomers and applied as catalyst in the hydrolysis of paraoxo
Guanidine based self-assembled monolayers on Au nanoparticles as artificial phosphodiesterases
Salvio, Riccardo,Cincotti, Antonio
, p. 28678 - 28682 (2014)
Gold nanoparticles passivated with a long chain alkanethiol decorated with a phenoxyguanidine moiety were prepared and investigated as catalysts in the cleavage of the RNA model compound HPNP and diribonucleoside monophosphates. The catalytic efficiency and the high effective molarity value of the Au monolayer protected colloids points to a high level of cooperation between the catalytic groups.
A unique nickel system having versatile catalytic activity of biological significance
Chattopadhyay, Tanmay,Mukherjee, Madhupama,Mondal, Arindam,Maiti, Pali,Banerjee, Arpita,Banu, Kazi Sabnam,Bhattacharya, Santanu,Roy, Bappaditya,Chattopadhyay,Mondai, Tapan Kumar,Nethaji, Munirathinam,Zangrando, Ennio,Das, Debasis
, p. 3121 - 3129 (2010)
A new dinuclear nickel(ll) complex, [Ni2(LH2)(H 2O)2(OH)(NO3)](NO3)3 (1), of an "end-off" compartmental ligand 2,6-bis(N-ethylpiperazine- iminomethyl)-4-methyl-phenolato, has been synthesized and structurally characterized. The X-ray single crystal structure analysis shows that the piperazine moieties assume the expected chair conformation and are protonated. The complex 1 exhibits versatile catalytic activities of biological significance, viz. catecholase, phosphatase, and DNA cleavage activities, etc. The catecholase activity of the complex observed is very dependent on the nature of the solvent. In acetonitrile medium, the complex is inactive to exhibit catecholase activity. On the other hand, in methanol, it catalyzes not only the oxidation of 3,5-ditert-buty !catechol (3,5-DTBC) but also tetrachlorocatechol (TCC), a catechol which is very difficult to oxidize, under aerobic conditions. UV-vis spectroscopic investigation shows that TCC oxidation proceeds through the formation of an intermediate. The intermediate has been characterized by an electron spray ionizaton-mass spectrometry study, which suggests a bidentate rather than a monodentate mode of TCC coordination in that intermediate, and this proposition have been verified by density functional theory calculation. The complex also exhibits phosphatase (with substrate p-nitrophenylphosphate) and DNA cleavage activities. The DNA cleavage activity exhibited by complex 1 most probably proceeds through a hydroxyl radical pathway. The bioactivity study suggests the possible applications of complex 1 as a site specific recognition of DNA and/or as an anticancer agent.
Mesoporous zeolites as enzyme carriers: Synthesis, characterization, and application in biocatalysis
Mitchell, Sharon,Pérez-Ramírez, Javier
, p. 28 - 37 (2011)
We study the application of hierarchical ZSM-5 zeolites, combining micropores and intracrystalline mesopores, as carriers for lipase enzymes compared with purely microporous ZSM-5 and mesoporous MCM-41. Strategies to improve enzyme immobilization by modif
Organoruthenium(II) compounds with pyridyl benzoxazole/benzthiazole moiety: studies on DNA/protein binding and enzyme mimetic activities
Gomathi, Asaithambi,Vijayan, Paranthaman,Viswanathamurthi, Periasamy,Suresh, Shanmugam,Nandhakumar, Raju,Hashimoto, Takeshi
, p. 1645 - 1666 (2017)
We report herein synthesis and characterization of four new organoruthenium(II) complexes of the type [RuH(CO)(PPh3)2(L1,2)]Cl (1, 3) and [Ru(CO)(Cl)2(AsPh3)(L1,2)] (2, 4) derived from the reaction of [RuHCl(CO)(EPh3)3] (E?=?P or As) with 2-(pyridine-2yl)benzoxazole (L1) and 2-(pyridine-2yl)benzthiazole (L2). Single-crystal X-ray diffraction data of 2 proved octahedral geometry of the complexes with a 1 : 1 ratio between the metal and the coordinated ligands. The binding affinities of 1–4 toward calf-thymus DNA (CT-DNA) and BSA were thoroughly studied by various spectroscopic techniques. Furthermore, the coordination compounds exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone and phosphatase-like activities in the hydrolysis of 4-nitrophenyl phosphate to 4-nitrophenolate ion. The kinetic parameters have been determined using Michaelis–Menten approach. The highest kcat values suggested that coordination compounds exhibit higher rates of catalytic efficacy.
Iron-catalyzed conversion of unactivated aryl halides to phenols in water
Ren, Yunlai,Cheng, Lin,Tian, Xinzhe,Zhao, Shuang,Wang, Jianji,Hou, Chaodong
, p. 43 - 45 (2010)
Although iron is low-cost and environmentally friendly, there is no report about iron-catalyzed conversion of unactivated aryl halides to phenols. In this Letter, a new method for the present conversion was developed with iron compounds as the catalyst and water as the solvent. The suggested method allowed a series of unactivated aryl bromides and aryl iodides to be converted into the corresponding substituted phenols in moderate to high yields.
Antibody catalyzed modification of amino acids. Efficient hydrolysis of tyrosine benzoate
Benedetti,Berti,Colombatti,Flego,Gardossi,Linda,Peressini
, p. 715 - 716 (2001)
Esterase antibody 522c2, the first example of a catalytic antibody specifically programmed to control the reactivity of functional groups on the side chain of tyrosine, accelerates the hydrolysis of benzoate esters of L-tyrosine and tyrosine-containing dipeptides by a factor of 104 and is moderately active against other benzoate esters.
Insights into Catalytic Hydrolysis of Organophosphonates at M-OH Sites of Azolate-Based Metal Organic Frameworks
Cao, Ran,Chen, Haoyuan,Farha, Omar K.,Islamoglu, Timur,Kirlikovali, Kent O.,Mian, Mohammad Rasel,Snurr, Randall Q.
, p. 9893 - 9900 (2021)
Organophosphorus nerve agents, a class of extremely toxic chemical warfare agents (CWAs), have remained a threat to humanity because of their continued use against civilian populations. To date, Zr(IV)-based metal organic framework (MOFs) are the most pre
Influence of Water Structure on Solvolysis in Water-in-Oil Microemulsions
Garcia-Rio, L.,Leis, J. R.,Iglesias, E.
, p. 12318 - 12326 (1995)
The kinetics of solvolysis of diphenylmethyl chloride, 4-nitrophenyl chloroformate, benzoyl chloride, p-anisoyl chloride, and bis(4-nitrophenyl)carbonate in water/AOT/isooctane microemulsions with various water/surfactant mole ratios W (AOT = sodium bis(2-ethylhexyl)sulfosuccinate) were interpreted by using a pseudophase model in which the substrates are assumed to be distributed between the isooctane and interface phases.The W-dependence of the intrinsic rate constants k for solvolysis at the interface depends on the solvolysis mechanism: for SN1 reactions, k decreased with W, which is attributed to decreasing polarity of the interface; contrariwise, SN2 reactions are accelerated by decreasing W, which is attributed to increasing nucleophilicity of interfacial water.
Hydrolysis of nitrophenyl esters catalyzed by modified cyclodextrin in water pools in reversed micelles
Nakamura,Sugama
, p. 4682 - 4685 (1984)
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Isolation and characterization of a beta-primeverosidase-like endo-manner beta-glycosidase from Aspergillus fumigatus AP-20.
Yamamoto, Shigeru,Okada, Masamichi,Usui, Taichi,Sakata, Kanzo
, p. 801 - 807 (2002)
A novel beta-glycosidase-producing microorganism was isolated from soil and identified as Aspergillus fumigatus AP-20 based on its taxonomical characteristics. The enzyme was found to be an extracellular protein in the culture of the isolated fungus and w
A strategic approach of enzyme engineering by attribute ranking and enzyme immobilization on zinc oxide nanoparticles to attain thermostability in mesophilic Bacillus subtilis lipase for detergent formulation
Khan, Mohd Faheem,Kundu, Debasree,Hazra, Chinmay,Patra, Sanjukta
, p. 66 - 82 (2019)
The present study envisaged rationalized protein engineering approach to attain thermostability in a mesophilic Bacillus subtilis lipase. Contributing amino acids for thermostability were analyzed from homologous thermophilic-mesophilic protein dataset th
Cellular zwitterionic metabolite analogs simultaneously enhance reaction rate, thermostability, salt tolerance, and substrate specificity of α-glucosidase
Deguchi, Eisuke,Koumoto, Kazuya
, p. 3128 - 3134 (2011)
We investigated the structural effects of metabolite analogs derived from a naturally-occurring zwitterionic metabolite, glycine betaine, on the activity of several hydrolases. The initial velocities of the hydrolases were enhanced by the addition of the
Kinetics and speciation of paraoxon hydrolysis by zinc(II)-azamacrocyclic catalysts
Kennedy, Daniel J.,Mayer, Brian P.,Baker, Sarah E.,Valdez, Carlos A.
, p. 123 - 131 (2015)
Four Zn2+-azamacrocyclic complexes were investigated for their ability to catalyze the hydrolysis of the toxic organophosphate (OP) pesticide diethyl paraoxon. Of the four complexes studied, Zn2+-1,5,9-triazacyclododecane (Zn2+-[12]aneN3) was found to be the most effective catalyst with a pseudo-first order reaction rate of k = 6.08 ± 0.23 × 10-4 min-1. Using 31P nuclear magnetic resonance (NMR) spectroscopy, the two products diethyl phosphate (DEP) and ethyl (4-nitrophenyl) phosphate (E4NPP) were identified for both catalyzed and background hydrolysis of paraoxon. Reaction rate and selectivity for formation of the non-toxic DEP were observed to correlate with catalyst pKa. The rate of formation of toxic E4NPP, however, was independent of both the presence and nature of the catalyst. The potential roles of buffer concentration and product inhibition were also investigated. Background hydrolysis at elevated reaction temperatures (50°C) displayed no preference for DEP over that of E4NPP despite substantial differences between the characteristics (i.e., pKa values) of the two leaving groups (ethoxide vs. 4-nitrophenoxide anions). As with previous observations of these types of metal-catalyzed hydrolyses, we invoke the formation of a trigonal bipyramidal-like transition state involving a Zn-coordinated phosphate bond, with the leaving group at the apical position and the incoming HO- anion approaching from the opposite end. Kinetic rates for catalytic hydrolysis display an overwhelming propensity for DEP formation, and suggest the importance of steric restrictions on transition state structure, namely a concerted arrangement of the azamacrocycle in opposition to the bulky 4-nitrophenoxy group.
Rationally Designed Double-Shell Dodecahedral Microreactors with Efficient Photoelectron Transfer: N-Doped-C-Encapsulated Ultrafine In2O3 Nanoparticles
Sun, Liming,Li, Rong,Zhan, Wenwen,Wang, Fan,Zhuang, Yuan,Wang, Xiaojun,Han, Xiguang
, p. 3053 - 3060 (2019)
It is desirable but challenging to design efficient micro-/nanoreactors for chemical reactions. In this study, we have fabricated mesoporous double-shelled hollow microreactors composed of N-doped-C-coated ultrafine In2O3 nanoparticles [N-C/In2O3 HD (hollow dodecahedron)] by the thermolysis of a dodecahedral In-based framework in Ar atmosphere. The obtained N-C/In2O3 HD exhibited excellent activity in the photocatalytic oxidative hydroxylation of a series of arylboronic acid substrates. This property can be attributed to its enhanced optical absorption and efficient separation of photo-generated electron–hole pairs, imparted by the unique structure and uniformly coated N-doped C layers. Furthermore, we found O2.? to be the critical active species in the process of photocatalytic oxidative hydroxylation of arylboronic acids, and the formation mechanism of this radical is also proposed. Theoretical calculations further confirmed that the N-doped C layer serves as an electron acceptor and revealed the microscopic charge-carrier migration path through the In2O3/N-doped graphite interfaces. Thus, photo-generated electrons from hybrid states of In2O3, composed of In 5s and 2p orbitals, are transferred into the hybrid states of N-doped graphite, composed of C 2p and N 2p orbitals. The present study may be helpful for understanding and designing carbon-based micro-/nanoreactors for photocatalytic reactions, and may also be useful for investigating related micro-/nanoreactors.
Use of MoO2Cl2(DMF)2 as a precursor for molybdate promoted hydrolysis of phosphoester bonds
Tome, Catia M.,Oliveira, M. Conceicao,Pillinger, Martyn,Goncalves, Isabel S.,Abrantes, Marta
, p. 3901 - 3907 (2013)
Phosphoester bond cleavage of para-nitrophenylphosphate (pNPP), a commonly used model substrate, is accelerated by using the complex MoO2Cl 2(DMF)2 (1) (DMF = dimethylformamide) as a hydrolysis promoting agent, even when c
Enzyme shielding in an enzyme-thin and soft organosilica layer
Correro, M. Rita,Moridi, Negar,Schützinger, Hansj?rg,Sykora, Sabine,Ammann, Erik M.,Peters, E. Henrik,Dudal, Yves,Corvini, Philippe F.-X.,Shahgaldian, Patrick
, p. 6285 - 6289 (2016)
The fragile nature of most enzymes is a major hindrance to their use in industrial processes. Herein, we describe a synthetic chemical strategy to produce hybrid organic/inorganic nanobiocatalysts; it exploits the self-assembly of silane building blocks at the surface of enzymes to grow an organosilica layer, of controlled thickness, that fully shields the enzyme. Remarkably, the enzyme triggers a rearrangement of this organosilica layer into a significantly soft structure. We demonstrate that this change in stiffness correlates with the biocatalytic turnover rate, and that the organosilica layer shields the enzyme in a soft environment with a markedly enhanced resistance to denaturing stresses. Important soft skills: Hybrid organic/inorganic nanobiocatalysts were created by the immobilization of enzymes on amino-modified silica nanoparticles and subsequent self-assembly and polycondensation of silane building blocks at the surface of the enzymes. The soft environment of the organosilica layer shielded the enzymes from denaturing stresses; however, the enzymes retained their conformational freedom and thus their catalytic activity (see picture).
Mesoporous Core-Shell Nanostructures Bridging Metal and Biocatalyst for Highly Efficient Cascade Reactions
Gao, Jing,Gao, Shiqi,Jiang, Yanjun,Liu, Yunting,Ma, Li,Wang, Zihan
, p. 1375 - 1380 (2020)
Mesoporous core-shell structured nanocatalysts with a PdPt bimetallic core and enzyme-immobilized polydopamine (PDA) shell were designed, in which the PDA shell worked as a barrier to position the bimetallic core and enzyme in separated locations. The accessible mesoporous structures of both the core and shell significantly facilitate mass transfer and catalyst utilization, improving the synergistic catalytic abilities in cascade reactions. The obtained bifunctional nanocatalysts enabled efficient two-step one-pot cascade reactions of different types: dynamic kinetic resolution of primary amines in organic solvent with high yield and enantioselectivity (up to 99% yield and 98% ee) and degradation of organophosphate nerve agent in aqueous solution with high rate constant and turnover frequency number values (0.8 min-1 and 20 min-1, respectively).
The mechanism by which 4-hydroxy-2,2,6,6-tetramethylpiperidene-1-oxyl (tempol) diverts peroxynitrite decomposition from nitrating to nitrosating species
Bonini, Marcelo G.,Mason, Ronald P.,Augusto, Ohara
, p. 506 - 511 (2002)
Tempol is a stable nitroxide radical that has been shown to protect laboratory animals from the injury associated with conditions of oxidative and nitrosoactive stress. Tempol's protective mechanisms against reactive oxygen species have been extensively studied, but its interactions with reactive nitrogen species remain little explored. Recently, it has been shown that tempol is a potent inhibitor of peroxynitrite-mediated phenol nitration while it increases phenol nitrosation by a complex mechanism [Carrol et al. (2000) Chem. Res. Toxicol. 13, 294]. To obtain further mechanistic insights, we reexamined the interaction of peroxynitrite with tempol in the absence and presence of carbon dioxide. Stopped-flow kinetic studies confirmed that tempol does not react directly with peroxynitrite but levels off the amount of oxygen (monitored with an oxygen electrode) and nitrite (monitored by chemiluminescence) produced from peroxynitrite in the presence and absence of carbon dioxide to about 30% and 70% of the initial oxidant concentration at pH 5.4, 6.4, and 7.4. Tempol inhibited phenol nitration while increasing the amounts of 4-nitrosophenol, that attained yields close to 30% of the peroxynitrite in the presence of carbon dioxide at pH 7.4. Fast-flow EPR experiments showed detectable changes in the instantaneous tempol concentration (maximum of 15%) only in the presence of carbon dioxide. Under these conditions, the instantaneous concentration of the carbonate radical anion was reduced by tempol in a concentration-dependent manner. The results indicate that tempol is oxidized by peroxynitrite-derived radicals (·OH and CO3·-, in the absence and presence of carbon dioxide, respectively) to the oxoammonium cation which, in turn, is reduced back to tempol while oxidizing peroxynitrite to oxygen and nitric oxide. The latter reacts rapidly with peroxynitrite-derived nitrogen dioxide to produce the nitrosating species, dinitrogen trioxide. Overall, the results support a role for peroxynitrite and its derived radicals in the tissue pathology associated with inflammatory conditions.
Inhibition of Yersinia protein tyrosine phosphatase by phosphonate derivatives of calixarenes
Vovk, Andriy I.,Kononets, Lyudmyla A.,Tanchuk, Vsevolod Yu.,Cherenok, Sergiy O.,Drapailo, Andriy B.,Kalchenko, Vitaly I.,Kukhar, Valery P.
, p. 483 - 487 (2010)
Inhibition of Yersinia protein tyrosine phosphatase by calix[4]arene mono-, bis-, and tetrakis(methylenebisphosphonic) acids as well as calix[4]arene and thiacalix[4]arene tetrakis(methylphosphonic) acids have been investigated. The kinetic studies reveal
Functional characterization of salt-tolerant microbial esterase WDEst17 and its use in the generation of optically pure ethyl (R)-3-hydroxybutyrate
Wang, Yilong,Xu, Yongkai,Zhang, Yun,Sun, Aijun,Hu, Yunfeng
, p. 769 - 776 (2018)
The two enantiomers of ethyl 3-hydroxybutyrate are important intermediates for the synthesis of a great variety of valuable chiral drugs. The preparation of chiral drug intermediates through kinetic resolution reactions catalyzed by esterases/lipases has been demonstrated to be an efficient and environmentally friendly method. We previously functionally characterized microbial esterase PHE21 and used PHE21 as a biocatalyst to generate optically pure ethyl (S)-3-hydroxybutyrate. Herein, we also functionally characterized one novel salt-tolerant microbial esterase WDEst17 from the genome of Dactylosporangium aurantiacum subsp. Hamdenensis NRRL 18085. Esterase WDEst17 was further developed as an efficient biocatalyst to generate (R)-3-hydroxybutyrate, an important chiral drug intermediate, with the enantiomeric excess being 99% and the conversion rate being 65.05%, respectively, after process optimization. Notably, the enantio-selectivity of esterase WDEst17 was opposite than that of esterase PHE21. The identification of esterases WDEst17 and PHE21 through genome mining of microorganisms provides useful biocatalysts for the preparation of valuable chiral drug intermediates.
β-D-GLUCOSIDASE-CATALYSED TRANSFER OF THE GLYCOSYL GROUP FROM ARYL β-D-GLUCO- AND β-D-XYLO-PYRANOSIDES TO PHENOLS
Aerts, Guido M.,Opstal, Omer Van,Bruyne, Clement K. De
, p. 221 - 234 (1982)
The effect of phenols on the hydrolysis of substituted phenyl β-D-gluco- and β-D-xylo-pyranosides by β-D-glucosidase from Stachybotrys atra has been investigated.Depending on the glycon part of the substrate and on the phenol substituent, the hydrolysis is either inhibited or activated.With aryl β-D-glucopyranosides, such transfer does not occur when phenols are used as acceptors, but it does occur with anilines.A two-steps mechanism, in which the first step is partially reversible, is proposed to explain these observations.A qualitative analysis of the various factors determing the overall effect of the phenol is given.
Evolution of metal complex-catalysts by dynamic templating with transition state analogs
Matsumoto, Masaomi,Estes, Deven,Nicholas, Kenneth M.
, p. 1847 - 1852 (2010)
The elicitation of hydrolytic catalysts from a dynamic library of imine-zinc(II) complexes (and their precursor aldehydes and amines) via templating with pro-transition state analogs (pro-TSA) is described. pro-TSA (2-pyridyl)phosphonate 2 amplifies a ben
Isoenzymes of pig-liver esterase reveal striking differences in enantioselectivities
Hummel, Anke,Bruesehaber, Elke,Boettcher, Dominique,Trauthwein, Harald,Doderer, Kai,Bornscheuer, Uwe T.
, p. 8492 - 8494 (2007)
(Graph Presented) An esterase toolbox: A set of isoenzymes of pig liver esterases (PLE) is identified, cloned, and overexpressed in E. coli. They show striking differences in enantioselectivity and enantiopreference in the kinetic resolution of acetates o
A Mechanistic Study on the Non-enzymatic Hydrolysis of Kdn Glycosides
Nejatie, Ali,Colombo, Cinzia,Hakak-Zargar, Benyamin,Bennet, Andrew J.
supporting information, (2022/01/13)
Sialic acids are biologically important carbohydrates that are prevalent throughout nature. We are interested in their intrinsic reactivity in aqueous solution and how such reactivity affects the design of substrates for investigation of enzymes that process these sugars. To probe the reactivity differences between two sialic acid family members N-acetylneuraminic acid and Kdn we measured the rate constants for hydrolysis of 4-nitrophenyl 3-deoxy-d-glycero-α-d-galacto-non-2-ulosonide in aqueous solution. The kinetic data is consistent with glycosidic C?O bond cleavage occurring via four mechanistic pathways, and these are: (i) hydronium ion-catalyzed hydrolysis of the neutral sugar; (ii) hydronium ion-catalyzed hydrolysis of the glycosidic carboxylate; (iii) water-catalyzed hydrolysis of the anionic glycoside; and (iv) base-promoted reaction of the anionic glycoside. To study the effects of C-5 substitution on the Kdn glycoside we made 4-nitrophenyl 5-O-methyl-α-Kdn glycoside and determined its rate constants for hydrolysis. All hydrolytic rate constants for both Kdn glycosides were larger than those reported for the parent N-acetyl-α-neuraminide. The water-catalyzed reaction (pathway iii) exhibited a βlg value of ?1.3±0.1. We conclude that the larger rate constants associated with C5-oxygen containing sialosides results from less steric congestion at the hydrolytic transition states than for the parent C-5 acetamido glycoside.
A copper nitride catalyst for the efficient hydroxylation of aryl halides under ligand-free conditions
Mitsudome, Takato,Mizugaki, Tomoo,Xu, Hang,Yamaguchi, Sho
supporting information, p. 6593 - 6597 (2021/08/10)
Copper nitride (Cu3N) was used as a heterogeneous catalyst for the hydroxylation of aryl halides under ligand-free conditions. The cubic Cu3N nanoparticles showed high catalytic activity, comparable to those of conventional Cu catalysts with nitrogen ligands, demonstrating that the nitrogen atoms in Cu3N act as functional ligands that promote hydroxylation.
Biochemical and biophysical characterisation of a small purified lipase from Rhizopus oryzae ZAC3
Ayinla, Zainab A.,Ademakinwa, Adedeji N.,Gross, Richard A.,Agboola, Femi K.
, (2021/02/16)
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