Structure and Activity of α-Chymotrypsin and Trypsin in Aqueous Organic Media

Simon, Lajos; Kotormán, Márta; Garab, G.; Laczkó, Ilona

doi:10.1006/bbrc.2001.4282

Cited by 109 publications

(90 citation statements)

References 23 publications

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“…The activities of α-chymotrypsin and trypsin first decreased and then increased with increasing ethanol concentration from 0% to 100%, in corresponding with the changes of the secondary structure elements (α-helix and β-sheet) [36]. Moreover, the apparent K m values of the two enzymes decreasing as the low ethanol concentrations were elevated, but then increased in the presence of higher ethanol concentrations, indicating the substrate affinity of the two enzymes first increased and then decreased with increasing ethanol concentrations [36].…”

Section: Effect Of the Functional Groups Of Organic Solventmentioning

confidence: 91%

Enzyme Stability and Activity in Non-Aqueous Reaction Systems: A Mini Review

et al. 2016

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Abstract:Enormous interest in biocatalysis in non-aqueous phase has recently been triggered due to the merits of good enantioselectivity, reverse thermodynamic equilibrium, and no water-dependent side reactions. It has been demonstrated that enzyme has high activity and stability in non-aqueous media, and the variation of enzyme activity is attributed to its conformational modifications. This review comprehensively addresses the stability and activity of the intact enzymes in various non-aqueous systems, such as organic solvents, ionic liquids, sub-/super-critical fluids and their combined mixtures. It has been revealed that critical factors such as Log P, functional groups and the molecular structures of the solvents define the microenvironment surrounding the enzyme molecule and affect enzyme tertiary and secondary structure, influencing enzyme catalytic properties. Therefore, it is of high importance for biocatalysis in non-aqueous media to elucidate the links between the microenvironment surrounding enzyme surface and its stability and activity. In fact, a better understanding of the correlation between different non-aqueous environments and enzyme structure, stability and activity can contribute to identifying the most suitable reaction medium for a given biotransformation.

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Section: Effect Of the Functional Groups Of Organic Solventmentioning

confidence: 91%

Enzyme Stability and Activity in Non-Aqueous Reaction Systems: A Mini Review

et al. 2016

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“…Trypsin is composed of two domains, in both of which 6 strands form an anti-parallel betabarrel in the native structure of trypsin [25][26][27]. Trypsin forms different secondary structures in organic solvents, depending on the nature and concentration of the solvent, circular dichroism (CD) measurements indicating that the extent of -sheet structure formation varies in the range 31-61% at pH 3.0 [28,29].…”

Section: Marta Kotormanamentioning

confidence: 99%

Amyloid-like Fibril Formation by Trypsin in Aqueous Ethanol. Inhibition of Fibrillation by PEG

Kotormán

Simon

Borics

et al. 2015

PPL

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Abstract:The formation of amyloid-like fibrils was studied by using the well-known serine protease trypsin as a model protein in the presence of ethanol as organic solvent. Trypsin forms amyloid-like fibrils in aqueous ethanol at pH = 7.0. The dye Congo red (CR) was used to detect the presence of amyloid-like fibrils in the samples. The binding of CR to fibrils led to an increase in absorption intensity and a red shift in the absorption band of CR. Thioflavin T (ThT) and 8-anilino-1-naphthalenesulfonic acid (ANS) binding assays were employed to characterize amyloid-like fibril formation. The ThT binding assay revealed that the protein exhibited maximum aggregation in 60% (v/v) ethanol after incubation for 24 h at 24 o C. The ANS binding results indicated that the hydrophobic residues were more exposed to the solvent in the aggregated form of the protein. The effects of polyethylene glycol (PEG) on the formation of amyloid-like fibrils was studied in vitro. The aggregation of trypsin was followed via the kinetics of aggregation, the far-UV circular dichroism (CD) and transmission electron microscopy (TEM) in the presence and absence of PEG. The CD measurements indicated that the protein aggregates have a cross-beta structure in 60% ethanol. TEM revealed that trypsin forms fibrils with a thread-like structure. The inhibitory effect of PEG on the aggregation of trypsin increased with rising PEG concentration. PEG therefore inhibits the formation of amyloid-like fibrils of trypsin in aqueous ethanol.

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“…Indeed, ethanol decreases the stability of protein but sugars increase it. [29][30][31][32] In general, the concentrations of ethanol and sugars in sake vary from batch to batch depending on the brewing conditions, such as the polishing rate of rice, the enzymatic activity of the koji, the fermentation temperature, and so on. We have also reported that ethanol promoted the inactivation of AGA, GA, AA, and ACP and that glucose depressed the inactivation of them, except for ACP, during heat treatment.…”

Section: Effects Of Ethanol and Glucose Concentrations On Inactivatiomentioning

confidence: 99%