Inhibition by N'-nitrosonornicotine of the catalytic activity of glutamate dehydrogenase in alpha-ketoglutarate amination.
The effect of N'-nitrosonornicotine (NNN), one of the tobacco-specific nitrosamines, on the catalytic activity of glutamate dehydrogenase (GLDH) in the alpha-ketoglutarate amination, using reduced nicotinamide adenine dinucleotide as coenzyme, was studied by a chronoamperometric method. The maximum reaction rate of the enzyme-catalyzed reaction and the Michaelis-Menten constant, or the apparent Michaelis-Menten constant, were determined in the absence and presence of NNN. NNN remarkably inhibited the bio-catalysis activity of GLDH, and was a reversible competitive inhibitior with K(i), estimated as 199 micromol l(-1) at 25 degrees C and pH 8.0.
Mao
You-An
YA
Postdoctorate Working Station, Changde Cigarette Factory, Changde 415000, China. youanmao@hotmail.com
Zhong
Ke-Jun
KJ
Wei
Wan-Zhi
WZ
Wei
Xin-Liang
XL
Lu
Hong-Bing
HB
D000586:Amination; D000818:Animals; D001667:Binding, Competitive; D002384:Catalysis; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005969:Glutamate Dehydrogenase / Q000037:antagonists & inhibitors*; D007656:Ketoglutaric Acids / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D009243:NAD / Q000378:metabolism; D009602:Nitrosamines / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D007656:Ketoglutaric Acids; D009602:Nitrosamines; D009243:NAD; D005969:Glutamate Dehydrogenase; C008655:N'-nitrosonornicotine