TY - JOUR
T1 - Effect of non-ionic detergents on apparent enzyme mechanism
T2 - V121A mutant of Streptomyces cholesterol oxidase endowed with enhanced sensitivity towards detergents
AU - Nishiya, Yoshiaki
AU - Yamashita, Mitsuo
AU - Murooka, Yoshikatsu
AU - Fujii, Isao
AU - Hirayama, Noriaki
PY - 1998/8
Y1 - 1998/8
N2 - One of the mutants of Streptomyces cholesterol oxidase with the Val121Ala mutation (V121A) was kinetically analysed. Although the reaction rate-substrate concentration curve of wild type follows a simple Michaelis-Menten equation, that of V121A is sigmoidal. The cooperativity was apparent and caused by non-ionic detergents that were used as a solvent of cholesterol. The concentration dependence of V121A on detergents was more significant than that of wild type, although the reaction rates of both enzymes decrease as the concentrations of detergents increase. Further experiments suggested that less hydrophobic interactions between V121A and detergents should be responsible for the apparent cooperativity. Since Val121 is in a hydrophobic loop located near the active site, the mutational effect is structurally discussed.
AB - One of the mutants of Streptomyces cholesterol oxidase with the Val121Ala mutation (V121A) was kinetically analysed. Although the reaction rate-substrate concentration curve of wild type follows a simple Michaelis-Menten equation, that of V121A is sigmoidal. The cooperativity was apparent and caused by non-ionic detergents that were used as a solvent of cholesterol. The concentration dependence of V121A on detergents was more significant than that of wild type, although the reaction rates of both enzymes decrease as the concentrations of detergents increase. Further experiments suggested that less hydrophobic interactions between V121A and detergents should be responsible for the apparent cooperativity. Since Val121 is in a hydrophobic loop located near the active site, the mutational effect is structurally discussed.
KW - Apparent cooperativity
KW - Cholesterol oxidase
KW - Mutational effect
KW - Non-ionic detergent
KW - Streptomyces
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U2 - 10.1093/protein/11.8.609
DO - 10.1093/protein/11.8.609
M3 - Article
C2 - 9749912
AN - SCOPUS:0031867401
VL - 11
SP - 609
EP - 611
JO - Protein Engineering, Design and Selection
JF - Protein Engineering, Design and Selection
SN - 1741-0126
IS - 8
ER -