[Kinetics of adrenodoxin reductase oxidation by non-physiologic electron acceptors].
The reactions of NADPH oxidation by quinones and inorganic complexes catalyzed by NADPH: adrenodoxin reductase were studied. The catalytic constant for the enzyme at pH 7.0 is 20-25 s-1; the oxidative constants for the quinones vary from 5 X 10(5) to 1.1 X 10(3) M-1 s-1 and show an increase with a rise in the one-electron acceptor reduction potential. The mode of adrenodoxin reductase interaction with oxyquinones differs from that of the enzyme interaction with alkyl-substituted quinones and inorganic complexes. NADPH competitively inhibits electron acceptors, whereas NADP+ is a competitive inhibitor of NADPH and a uncompetitive inhibitor of electron acceptors. (Ki = 25 microM). The depth of FAD incorporation into the enzyme molecule as calculated according to the outer sphere electron transfer theory is 6.1 A.
D000302:Adrenal Cortex / Q000201:enzymology; D000818:Animals; D002417:Cattle; D004579:Electron Transport; D005287:Ferredoxin-NADP Reductase / Q000378:metabolism*; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D010084:Oxidation-Reduction; D011809:Quinones / Q000378:metabolism
D011809:Quinones; D005287:Ferredoxin-NADP Reductase; D009247:NADH, NADPH Oxidoreductases
Kinetika okisleniia adrenodoksinreduktazy nefiziologicheskimi aktseptorami élektronov.