Effects of added albumin on the kinetic isotope effect observed in the microsomal oxidative demethylation of the methoxyl group.
The kinetic deuterium isotope effect on the microsomal oxidative demethylation of methoxyl groups was measured using methoxychlor, an insecticide, as a model compound. When the metabolic reactions were conducted in the presence of bovine serum albumin, the observed isotope effect was smaller than that in its absence. The values were unaltered when the albumin concentration was changed from 1% to 2%. The results were interpreted by the alteration of the ES-complex formation/dissociation rate with the interaction between substrate and albumin.
Kurihara
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Radioisotope Research Center, Kyoto University, Japan.
D000818:Animals; D001711:Biotransformation; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003903:Deuterium; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D008297:Male; D008433:Mathematics; D008731:Methoxychlor / Q000378:metabolism*; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D011865:Radioisotope Dilution Technique; D051381:Rats; D017208:Rats, Wistar; D012710:Serum Albumin, Bovine / Q000494:pharmacology*
D012710:Serum Albumin, Bovine; D003577:Cytochrome P-450 Enzyme System; D003903:Deuterium; D008731:Methoxychlor