title: Inhibition of camel lens zeta-crystallin/NADPH:quinone oxidoreductase activity by chloranilic acid.
abstract: Camel lens zeta-crystallin/NADPH:quinone oxidoreductase activity was inhibited by chloranilic acid (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) with NADPH as an electron donor and 9,10-phenanthrenequinone (PQ) as an electron acceptor in a time-independent but concentration dependent manner. The IC50 of chloranilic acid was 1 microM. The inhibition was noncompetitive with respect to both NADPH and PQ as deduced by Lineweaver-Burk plots. The estimated inhibition constant (Ki) was 0.8 microM for both NADPH and PQ. Examination of other benzoquinones suggested that the presence of -OH and -Cl on benzoquinone was essential for the inhibition.
authors.affiliation: Department of Science, King Khalid Military Academy, Riyadh, Kingdom of Saudi Arabia.
authors.forename: A A
authors.initials: AA
authors.lastname: al-Hamidi
authors.forename: A S
authors.initials: AS
authors.lastname: Riskuwa
authors.forename: S D
authors.initials: SD
authors.lastname: Ali
mesh_terms: D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology*; D002162:Camelus; D002703:Chloranil / Q000494:pharmacology; D003459:Crystallins / Q000037:antagonists & inhibitors*; D007700:Kinetics; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000037:antagonists & inhibitors*
chemical_list: D016227:Benzoquinones; D003459:Crystallins; D002703:Chloranil; C105931:tetrahydroxy-1,4-benzoquinone; D016660:NAD(P)H Dehydrogenase (Quinone); C014400:chloranilic acid