[Various kinetic properties of beta-glucosidase cloned from Clostridium thermocellum in E. coli].
The kinetics of pNPG, pNPX and cellobiose hydrolysis by beta-glucosidase cloned from C. thermocellum into E. coli was studied. The V values for these substrate hydrolysis are 102, 357 and 6.7 mumols/min/mg protein, respectively; Km are 0.44 mM, 50 mM and 100 mM, respectively, sigma-Gluconolactone inhibits the hydrolysis of all substrates according to a competitive mechanism with Ki of 0.032 mM, 6.0 mM and 0.25 mM, respectively. Glucose inhibits the hydrolysis of pNPG and pNPX also via a competitive mechanism with Ki of 10 mM and 37 mM, while cellobiose--via a mixed type mechanism with Ki of 110 mM and 350 mM. The existence of separate adsorption sites for each substrate and of a common catalytic site for pNPG and pNPX hydrolysis is supposed.
Kataeva
I A
IA
Golovchenko
N P
NP
Akimenko
V K
VK
D003001:Cloning, Molecular; D003013:Clostridium / Q000201:enzymology*; D004926:Escherichia coli / Q000235:genetics; D006868:Hydrolysis; D007700:Kinetics; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D001617:beta-Glucosidase
Nekotorye kineticheskie svoĭstva beta-gliukozidazy, klonirovannoĭ iz Clostridium thermocellum v E. coli.