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. 1973 Oct;136(2):371–379. doi: 10.1042/bj1360371

The effect of magnesium ions on the diemthylaniline oxidation rate and electron transfer in liver microsomal fraction

A I Archakov 1, I I Karuzina 1, I S Kokareva 1, G I Bachmanova 1
PMCID: PMC1165963  PMID: 4149444

Abstract

1. Reactions of N-demethylation, p-hydroxylation and N-oxidation of one substrate, i.e. dimethylaniline, have been used to show that the activating effect of Mg2+ takes place only in the first two reactions. 2. An increase in Vmax. of N-demethylation of dimethylaniline is accompanied by an increase in Km. In the p-hydroxylation of dimethylaniline Vmax. increases whereas Km does not change. A comparison of the changes in the Km values of these reactions with the change in Ks shows that in both cases Km does not characterize the affinity of cytochrome P-450 for dimethylaniline. 3. The rate-limiting site of N-demethylation and p-hydroxylation of dimethylaniline, as well as the total rate of NADPH oxidation in the presence of dimethylaniline, is between cytochromes b5 and P-450. Addition of Mg2+ to the incubation medium changes the hydrophobic environment of phosphatidylcholine in the membrane, the process being accompanied by a sharp increase in the fluorescence quantum yield of 8-anilinonaphthalene-1-sulphonate.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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