Carbon monoxide binding to pentacoordinate mercaptide-heme complexes: kinetic study on models for cytochrome P-450.

AUTOR(ES)

Chang, C K

RESUMO

Mercaptide anions form exclusively penta-coordinate heme complexes [RS-heme] in polar and nonpolar solution over a wide range of mercaptide concentration. These complexes have a Soret peak at 408 nm and a formation constant of about 2.5 X 10(4) M(-1), and combine with CO to give a CO-cytochrome P-450 type spectrum. Kinetics of CO binding to mercaptide-heme complexes [RS-heme] have been studied by the flash photolysis method. Characteristic constants for this reaction suggest close similarities between [CH3-(CH2)3-S-heme] and cytochrome P-450. The reaction of alkoxide anion with heme has also been examined but no evidence was found for the existence of the [RO-heme-CO[ species.

Documentos Relacionados

• Phosphorylation of hepatic phenobarbital-inducible cytochrome P-450.
• Kinetics of carbon monoxide binding to phenobarbital-induced cytochrome P-450 from rat liver microsomes: a simple bimolecular process.
• Self-catalyzed destruction of cytochrome P-450: covalent binding of ethynyl sterols to prosthetic heme.
• Hydrocarbon formation in the reductive cleavage of hydroperoxides by cytochrome P-450.
• Identification and characterization of cDNA clones specific for cholesterol side-chain cleavage cytochrome P-450.