Kinetic mechanism of glucose dehydrogenase from Halobacterium salinarum.
The kinetic mechanism of glucose dehydrogenase (EC 1.1.1.47) from Halobacterium salinarum was studied by initial velocity and product inhibition methods. The results suggest that both, in the forward and reverse direction, the reaction mechanism is of Bi Bi sequential ordered type involving formation of ternary complexes. NADP+ adds first and NADPH formed dissociates from the enzyme last. For the reverse direction, NADPH adds first and NADP+ leaves last. Product inhibition experiments indicate that (a), the coenzymes compete for the same site and form of the enzyme and (b), ternary abortive complexes of enzyme-NADP(+)-glucono-delta-lactone and enzyme-NADPH-glucose are formed. All the other inhibitions are noncompetitive.
Bhaumik
S R
SR
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai.
Sonawat
H M
HM
D042843:Glucose 1-Dehydrogenase; D005948:Glucose Dehydrogenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006217:Halobacterium / Q000201:enzymology*; D007700:Kinetics; D009249:NADP / Q000378:metabolism; D012965:Sodium Chloride; D013379:Substrate Specificity
D012965:Sodium Chloride; D009249:NADP; D005948:Glucose Dehydrogenases; D042843:Glucose 1-Dehydrogenase