Inhibition of aspartate transcarbamylase by a phenobarbital derivative.
Mammalian and hepatic aspartate transcarbamylase is inhibited by phenobarbital p-nitrophenylhydrazone in a reversible and non-competitive type with Ki values 8.45 x 10(-5) and 9.64 x 10(-5) M in the reactions toward carbamyl phosphate and aspartate, respectively. In vivo inhibition occurred in a dose-dependent manner in which less than 50% of the activity was retained. These observations suggest that this inhibitor may interfere with the in vivo regulation of this enzyme and lead to an additional biological effect of phenobarbitals.
Balbaa
M
M
Department of Biochemistry, Faculty of Science, Alexandria University, Alexandria, Egypt. mahmoudbalbaa@usa.net
Yacout
G
G
Ghonaim
T
T
Othman
D
D
D000818:Animals; D001221:Aspartate Carbamoyltransferase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D015394:Molecular Structure; D010634:Phenobarbital / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology
D004791:Enzyme Inhibitors; D001221:Aspartate Carbamoyltransferase; D010634:Phenobarbital