Catalytic activity and denaturation of enzymes in water/organic cosolvent mixtures. Alpha-chymotrypsin and laccase in mixed water/alcohol, water/glycol and water/formamide solvents.
The dependence of the catalytic activities of alpha-chymotrypsin and laccase on the concentration of organic cosolvents (alcohols, glycols and formamides) in mixed aqueous media has a pronounced threshold character: it does not change up to a critical concentration of the non-aqueous cosolvents added, yet further increase of the latter (by only a small percentage, by vol.) leads to an abrupt decrease in enzyme activity. Fluorescence studies indicate that the inactivation results from reversible conformational changes (denaturation) of the enzymes. There is a linear correlation between the critical concentration of residual water (at which the enzyme inactivation occurs in a threshold manner) and the hydrophobicity of the organic cosolvents added. A quantitative criterion is suggested for the selection of organic cosolvents to be used for enzymatic reactions in homogeneous water/organic solvent media.
Mozhaev
V V
VV
Chemistry Department, Moscow State University, USSR.
Khmelnitsky
Y L
YL
Sergeeva
M V
MV
Belova
A B
AB
Klyachko
N L
NL
Levashov
A V
AV
Martinek
K
K
D000438:Alcohols / Q000494:pharmacology; D002918:Chymotrypsin; D005453:Fluorescence; D005559:Formamides / Q000494:pharmacology; D006018:Glycols / Q000494:pharmacology; D042845:Laccase; D010088:Oxidoreductases; D011489:Protein Denaturation; D012995:Solubility; D012997:Solvents / Q000494:pharmacology*
D000438:Alcohols; D005559:Formamides; D006018:Glycols; D012997:Solvents; D010088:Oxidoreductases; D042845:Laccase; D002918:Chymotrypsin