title: [Spectral interactions of cytochrome P-450 with n-heptane and methanol].
abstract: Methanol interacts with cytochrome P-450 to produce the reversed type I spectral change. In the presence of type I substrate n-heptane, the methanol induced spectrum disappears without detectable effects of interaction suggesting that methanol is a very weak ligand for heme iron of cytochrome P-450. Methanol strongly lowers the apparent spectral dissociation constant (Ks app) of n-heptane binding with rat liver cytochrome P-450 both in control and C6-C9 petroleum fraction inhaled group. In control group, titration of cytochrome P-450 with methanolic solutions of n-heptane does not change the maximal spectral interaction (Amax) observed with pure n-heptane. However in the inhaled group during titration of induced cytochrome P-450 with methanolic solutions of n-heptane an additional type I spectral change is observed. Thus addition of "equivalent" amounts of methanol into the reference cuvette during titration with methanolic solutions overestimates the true magnitude of type I spectral change of cytochrome P-450 with n-heptane.
authors.affiliation: Zakładu Tokaykologii Instytutu Biofarmacji, Akademii Medycznej w Warszawie.
authors.forename: M M
authors.initials: MM
authors.lastname: Szutowski
authors.forename: D
authors.initials: D
authors.lastname: Brzdekiewicz
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis / Q000378:metabolism*; D004347:Drug Interactions; D006536:Heptanes / Q000008:administration & dosage / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D000432:Methanol / Q000008:administration & dosage / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006536:Heptanes; C028618:n-heptane; D003577:Cytochrome P-450 Enzyme System; D000432:Methanol
vernacular_title: Interakcje spektralne cytochromu P-450 z n-heptanem i metanolem.