Rate parameter changes by added albumin in the microsomal oxidative demethylation of deuteriated and non-deuteriated 4-methoxyanisole

Article abstract of DOI:10.1271/bbb.60.806

Bovine serum albumin (BSA) added to the reaction medium for the oxidative demethylation of 4-methoxyanisole and its 'di-CD₃' isotopomer ([d₆]methoxyanisole), when catalyzed by liver microsomes from untreated rats, decreased the K(m) values and increased the V(max)/K(m)(= V/K) values. The V(max) values were not markedly altered. The values for the deuterium isotope effect on V(max) and V/K for the reaction with this isotopomer were between 2.2 and 2.8, and that on K(m) was close to unity. The magnitude of the isotope effect was not significantly changed by adding BSA. The intramolecular isotope effect with [mono-CD₃]4-methoxyanisole ([d₃]methoxyanisole) in liver microsomes from untreated rats was between 10.3 and 10.8, which was not significantly changed by BSA. Liver microsomes from rats treated with phenobarbital resulted in the intramolecular isotope effect value in the absence of BSA being between 7.2 and 9.1, which was not significantly altered by BSA. Based on these data, the calculated apparent rate constant for the enzyme-substrate complex formation was markedly increased by up to about 1.9- and 3.5-fold by 1% and 2% of BSA added, respectively.

Full text of DOI:10.1271/bbb.60.806

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Rate Parameter Changes by Added Albumin in the
Microsomal Oxidative Demethylation of Deuteriated
and Non-deuteriated 4-Methoxyanisole
Masatoshi Masudaa, Daisuke Kishimotoa & Norio Kuriharab
a Department of Agricultural Chemistry, and Radioisotope Research Center, Kyoto
University, Yoshida Konoecho, Sakyo-ku, Kyoto 606–01, Japan
b Radioisotope Research Center, Kyoto University, Yoshida Konoecho, Sakyo-ku, Kyoto
606–01, Japan
Published online: 12 Jun 2014.
To cite this article: Masatoshi Masuda, Daisuke Kishimoto & Norio Kurihara (1996) Rate Parameter Changes by Added
Albumin in the Microsomal Oxidative Demethylation of Deuteriated and Non-deuteriated 4-Methoxyanisole, Bioscience,
Biotechnology, and Biochemistry, 60:5, 806-810, DOI: 10.1271/bbb.60.806
To link to this article: http://dx.doi.org/10.1271/bbb.60.806
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