926-61-4Relevant academic research and scientific papers
Degradation of pyrimidines in Saccharomyces kluyveri: Transamination of β-alanine
Schnackerz,Andersen,Dobritzsch,Piskur
, p. 794 - 799 (2008)
Beta-alanine is an intermediate in the reductive degradation of uracil. Recently we have identified and characterized the Saccharomyces kluyveri PYD4 gene and the corresponding enzyme β-alanine aminotransferase (SkPyd4p), highly homologous to eukaryotic γ-aminobutyrate aminotransferase (GABA-AT). S. kluyveri has two aminotransferases, GABA aminotransferase (SkUga1p) with 80% and SkPyd4p with 55% identity to S. cerevisiae GABA-AT. SkPyd4p is a typical pyridoxal phosphate-dependent aminotransferase, specific for α-ketoglutarate (αKG), β-alanine (BAL) and γ-aminobutyrate (GABA), showing a ping-pong kinetic mechanism involving two half-reactions and substrate inhibition. SkUga1p accepts only αKG and GABA but not BAL, thus only SkPydy4p belongs to the uracil degradative pathway. Copyright Taylor & Francis Group, LLC.
Kinetics and Mechanism of Electron Transfer Reactions in Aqueous Solutions: Silver(I) Catalyzed Oxidation of Aspartic Acid by Cerium(IV) in Acid Perchlorate Medium
Sharma, Indu,Devra, Vijai,Gupta, Divya,Gangwal, C. M.,Sharma, P. D.
, p. 311 - 320 (1995)
Silver(I) catalyzed oxidation of aspartic acid by cerium(IV) was studied in acid perchlorate medium.The stoichiometry of the reaction is represented by the eq. (i), (i) R-CHNH3+COOH + 2 Ce(IV) -H2O-> R-CHO + NH4+ + CO2 + 2 Ce(III) + 2 H+.Dimeric cerium(IV) species has been indicated and employed in calculations of monomeric cerium(IV) species concentrations.The reaction is second-order and uncatalyzed reaction also simultaneously occurs along with silver(I) catalyzed reaction conforming to the rate law (ii), (ii) , where k is an observed second-order rate constant.A probable reaction mechanism is suggested.
Autocatalytic oxidation of β-alanine by peroxomonosulfate in the presence of copper(II) ion
Sayee Kannan,Easwaramoorthy,Vijaya,Ramachandran
, p. 44 - 49 (2008)
Kinetics and mechanism of oxidation of β-alanine by peroxomonosulfate (PMS) in the presence of Cu(II) ion at pH 4.2 (acetic acid/sodium acetate) has been studied. Autocatalysis was observed only in the presence of copper(II) ion, and this was explained due to the formation of hydroperoxide intermediate. The rate constant for the catalyzed (k2obs) and uncatalyzed (K1obs) reaction has been calculated. The kinetic data obtained reveal that both the reactions are first order with respect to IPMS]. K1obs values initially increase with the increase in [β-alanine] and reach a limiting value, but k2obs values decrease with the increase in [β-alanine]. k1 obs values increase linearly with the increase in [Cu(II)], whereas k2obs values increase with [Cu(II)]2. Furthermore, k1obsvalues are independent of [acetate], but K2obs values decrease with the increase in acetate. A suitable mechanism has been proposed to explain the experimental observation. The reaction has been studied at different temperatures, and the activation parameters are calculated.
Oxidation of L-Aspartic Acid and L-Glutamic Acid by Manganese(III) Ions in Aqueous Sulphuric Acid, Acetic Acid, and Pyrophosphate Media: A Kinetic Study
Sherigara, B. S.,Bhat, K. Ishwar,Pinto, Ivan,Gowda, N. M. Made
, p. 675 - 690 (1995)
Kinetics of oxidation of L-aspartic acid and L-glutamic acid by manganese(III) ions have been studied in aqueous sulphuric acid, acetic acid, and pyrophosphate media.Manganese(III) solutions were prepared by known electrolytic/chemical methods in the three media.The nature of the oxidizing species present in manganese(III) solutions was determined by spectrophotometric and redox potential measurements.The raction shows a variable order in 0: the order changes from two to one as the reactive oxidizing species changes from an aquo ionic form to a complex form.There is a first-order dependence of the rate on 0 in all the three media while the other common features include an inverse dependence each on and on .Effects of varying ionic strength and solvent composition were studied.Added anions such as pyrophosphate, fluoride, or chloride alter the reaction rate and mechanism by changing the formal redox potential of Mn(III)-Mn(II) couple.Activation parameters have been evaluated using the Arrhenius and Eyring plots.Mechanisms consistent with the kinetic data have been proposed and discussed.
Interaction between Pyridoxal Hydrochloride and L-α-Asparagine in Comparison to L-α- and D-α-Aspartic Acids
Pishchugin,Tuleberdiev
, p. 49 - 54 (2021/02/26)
Abstract: The kinetics and mechanism of condensation of pyridoxal hydrochloride with L-α-asparagine, L?α- and D-α-aspartic acids are analyzed via UV spectroscopy and polarimetry. It is found that L?α?asparagine containing α-NH2 and γ-NH2/
Kinetic and mechanistic studies on the oxidation of DL-aspartic acid with manganese(III) in sulphuric acid medium
Makena, Rama Rajeswari,Rambabu, Rallabandi,Vani, Parvataneni
, p. 1073 - 1078 (2020/06/26)
The kinetics of oxidation of DL-aspartic acid by manganese(III) was studied spectrophotometrically at 500 nm in sulphuric acid medium at 40oC. The reaction was observed to be fractional order with respect to substrate and first order with respect to oxidant. Further the rate of reaction found to decrease with increase in ionic strength and [H+], while [HSO4-] and [MnII] were found to have negligible effect. The energy of activation, Ea and the entropy of activation, ΔS# computed from thermal studies were found to be 102.23±11.1 KJ mol-1 and 18.45±35.40 JK-1 mol-1 respectively.
MICROORGANISMS AND METHODS FOR PRODUCTION OF 4-HYDROXYBUTYRATE, 1,4-BUTANEDIOL AND RELATED COMPOUNDS
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Page/Page column, (2015/06/03)
The invention provides non-naturally occurring microbial organisms having a 4-hydroxybutyrate, 1,4-butanediol, or other product pathway and being capable of producing 4-hydroxybutyrate, 1,4-butanediol, or other product, wherein the microbial organism comprises one or more genetic modifications. The invention additionally provides methods of producing 4-hydroxybutyrate, 1,4-butanediol, or other product or related products using the microbial organisms.
Substrate profile of an ω-transaminase from Burkholderia vietnamiensis and its potential for the production of optically pure amines and unnatural amino acids
Jiang, Jinju,Chen, Xi,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
, p. 32 - 39 (2014/01/06)
A new (S)-enantioselective ω-transaminase (ω-TA) gene from Burkholderia vietnamiensis G4 was functionally expressed in Escherichia coli BL21 (DE3), and the purified recombinant N-terminal His-tagged ω-TA (HBV-ω-TA) had a dimeric structure with optimum pH and temperature of 8.4 and 40 C, respectively. The enzyme showed higher activities toward aromatic amines than aliphatic amines and (S)-1-methylbenzylamine ((S)-α-MBA) was the most active amino donor. For amino acceptor, keto acids, keto esters and aldehydes were more reactive than ketones with pyruvate ethyl ester being most active. Several chiral amines and unnatural amino acids or esters were synthesized using HBV-ω-TA as the catalyst and isopropylamine or (S)-α-MBA as amino donor. Notably, HBV-ω-TA catalyzed the amino transfer to β-keto esters to give optically pure β-amino acid esters. In addition, glyoxylate was used as amino acceptor for the first time in the kinetic resolution of racemic amines and optically pure amines, such as (R)-1-methylbenzylamine, (R)-1-phenylpropylamine, (R)-2-amino-4-phenylbutane and (R)-1-aminotetraline, were obtained.
Kinetics and mechanism of oxidation of malic acid by N-bromoanisamide
Malviya,Siriah,Badole
, p. 767 - 770 (2013/11/06)
The kinetics of the oxidation of the malic and by N-bromoanisamide in HC1O4 and in the presence of Hg(OAc)2 have been studied. The reactions exhibit a first order rate dependence with respect to the oxidant and substrate. The reactions are acid catalyzed and retarded by the addition of anisamide, a byproduct of reaction. The rate of oxidation decreases with decrease in dielectric constant of the medium. The effect of temperature on the reaction has been investigated in the temperature range 313-328 K. The stoichiometric studies revealed 1:1 mole ratio. Various thermodynamic parameters have been computed and a possible operative mechanism is proposed.
Aggregation in oxidation of aspartic and glutamic acids by chloramine-T in presence of surfactants: A kinetic study
Pandey, Ekta,Grover, Neeti,Kambo, Neelu,Upadhyay, Santosh K.
, p. 1186 - 1192 (2007/10/03)
The kinetics of oxidation of aspartic and glutamic acids by chloramine-T in HClO4 medium have been investigated in the absence and presence of anionic (sodium lauryl sulphate), cationic (cetyltrimethylammonium bromide) and non-ionic (Brij 35) surfactants. In the absence of surfactant the rate of oxidation may be represented as, d[Chloramine-T]/dt=k[Chloramine-T] 2[Amino acid]/(1+K[H+]) where k and K are constants. The presence of a small amount of surfactant (below its critical micelle concentration) strongly enhances the rate of oxidation and the observed rate constant attains constancy at higher surfactant concentration. Using Piszkiewicz's cooperativity model, the cooperative index n has been calculated for these reactions to be between 1-3, indicating the existence of catalytically productive submicellar aggregates. The values of n have been used to calculate the binding constants of reactants with the surfactant using Raghvan and Srinivasan's model proposed for biomolecular micellar catalysed reactions. The evaluated binding constants are in good agreement from those obtained by Piszkiewicz's model. The formation of aggregate is further supported by the enhancement of rate in presence of a common hydrotrope, namely, sodium benzoate.
