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Belyaeva, E. A.; Gra, D. V.; Еремеев, Н. Л.

doi:10.1023/a:1020530220774

Cited by 11 publications

(5 citation statements)

References 10 publications

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“…In this sense, it is interesting to note that similar results were obtained by Eremeev et al [32] for the α-CTcatalyzed hydrolysis of different substrates in mixtures of homogeneous solvents; i.e., bell-shaped or continuously decreasing v 0 rates were observed depending on the substrate considered.…”

Section: Resultssupporting

confidence: 82%

Kinetics of N-glutaryl-L-phenylalanine p-nitroanilide hydrolysis catalyzed by α-chymotrypsin in aqueous solutions of dodecyltrimethylammonium bromide

Abuín

Lissi

Duarte

2005

Journal of Colloid and Interface Science

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Section: Resultssupporting

confidence: 82%

Kinetics of N-glutaryl-L-phenylalanine p-nitroanilide hydrolysis catalyzed by α-chymotrypsin in aqueous solutions of dodecyltrimethylammonium bromide

Abuín

Lissi

Duarte

2005

Journal of Colloid and Interface Science

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“…In previous studies 7,18,19 , the mechanism of 2-NA hydrolysis where S stands for the substrate, E for the enzyme, SE for the enzyme-substrate complex, S′E for the acyl-enzyme intermediate and P1 and P2 for the basic and acidic products, respectively. Further these authors proposed that the effect of surfactant DTAB on the enzymatic activity occurs in the last step owing to the increase in the rate constant k3.…”

Section: Enzymatic Activity Of α-Ct In 12-10-12 Solutionmentioning

confidence: 99%

Enzymatic Superactivity and Conformational Change of <i>α</i>-CT Induced by Cationic Gemini Surfactant

Bai¹,

河南师范大学化学化工学院²,

Liu³

et al. 2017

Acta Physico-Chimica Sinica

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癸二铵，简写为 12-10-12)相互作用热力学的关系。酶活性通过紫外-可见吸收光谱法测量底物醋酸 2-萘酯(2-NA)分解速率进行评估。在较短的培育时间内，12-10-12 能够激活 α-CT，得到催化 2-NA 分解的超活性，同时也加速了酶变性的动力学过程。在低于 α-CT/12-10-12 体系的临界聚集浓度(cac12-10-12,CT)时，显示一个钟形的大的超活性区。酶活性随时间变化的结果表明，由 12-10-12 激活的 α-CT 有高的酶活性和低的变性稳定性。进而采用等温滴定量热(ITC)、稳态荧光光谱和差示扫描量热(DSC)技术研究了 12-10-12 诱导 α-CT 超活性的机理。结果表明酶的超活性来源于正电荷的 12-10-12 与 α-CT 相互作用对 α-CT 内部结构的扰动，使得酶的构象变得比处于弱相互作用平衡的天然酶的构象更加松弛，这有利于 2-NA 水解酸性产物释放的动力学，而同时也导致了 α-CT 结构的不稳定性。关键词：表面活性剂；α-糜蛋白酶；超活性；等温滴定量热；稳态荧光；差示扫描量热中图分类号：O642；O648

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“…Although some studies have been conducted, for example, for the kinetic behaviour of alpha-chymotrypsin in organic solvents,22 up to now it was not possible to generalize the influence of organic solvents on enzyme behaviour. Mechanistic explanations are only applicable for very specific systems23 and solvent effects in general are by no means completely understood.…”

Section: Introductionmentioning

confidence: 99%

Influence of Organic Solvents on Enzymatic Asymmetric Carboligations

et al. 2012

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The asymmetric mixed carboligation of aldehydes with thiamine diphosphate (ThDP)-dependent enzymes is an excellent example where activity as well as changes in chemo- and stereoselectivity can be followed sensitively. To elucidate the influence of organic additives in enzymatic carboligation reactions of mixed 2-hydroxy ketones, we present a comparative study of six ThDP-dependent enzymes in 13 water-miscible organic solvents under equivalent reaction conditions. The influence of the additives on the stereoselectivity is most pronounced and follows a general trend. If the enzyme stereoselectivity in aqueous buffer is already >99.9% ee, none of the solvents reduces this high selectivity. In contrast, both stereoselectivity and chemoselectivity are strongly influenced if the enzyme is rather unselective in aqueous buffer. For the S-selective enzyme with the largest active site, we were able to prove a general correlation of the solvent-excluded volume of the additives with the effect on selectivity changes: the smaller the organic solvent molecule, the higher the impact of this additive. Further, a correlation to log P of the additives on selectivity was detected if two additives have almost the same solvent-excluded volume. The observed results are discussed in terms of structural, biochemical and energetic effects. This work demonstrates the potential of medium engineering as a powerful additional tool for varying enzyme selectivity and thus engineering the product range of biotransformations. It further demonstrates that the use of cosolvents should be carefully planned, as the solvents may compete with the substrate(s) for binding sites in the enzyme active site.

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Untitled

Cited by 11 publications

References 10 publications

Kinetics of N-glutaryl-L-phenylalanine p-nitroanilide hydrolysis catalyzed by α-chymotrypsin in aqueous solutions of dodecyltrimethylammonium bromide

Kinetics of N-glutaryl-L-phenylalanine p-nitroanilide hydrolysis catalyzed by α-chymotrypsin in aqueous solutions of dodecyltrimethylammonium bromide

Enzymatic Superactivity and Conformational Change of <i>α</i>-CT Induced by Cationic Gemini Surfactant

Influence of Organic Solvents on Enzymatic Asymmetric Carboligations

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