Microsomes from liver or kidney of untreated rainbow trout hydroxylated lauric acid specifically at the (ω-1) position. Turnover numbers for liver (2.72 min-1) and kidney (14.1 min-1) were decreased seven- and twofold, respectively, following treatment with β-naphthoflavone. Laurate hydroxylation activity from untreated trout hepatic microsomes was sensitive to inhibition by SKF-525A, but was not sensitive to metyrapone and only partially inhibited by α-naphthoflavone. The temperature optimum of laurate (ω-1) hydroxylation in trout liver microsomes was 25-30 °C. The Km and Vmax for (ω-1)-hydroxylaurate formation was 50 μm and 1.63 nmol min-1 mg-1, respectively, in liver and 20 μm and 3.95 nmol min-1 mg-1, respectively, in kidney from untreated trout microsomes. (ω-1) Hydroxylation of laurate, in both liver and kidney microsomes, was sensitive to an antibody raised against a previously purified cytochrome P-450 isozyme (LM2) of trout liver microsomes, which has been shown to be active towards aflatoxin B1. Antibody to the major isozyme of cytochrome P-450 (LM4b, active towards benzo(a)pyrene) induced by β-naphthoflavone did not inhibit (ω-1) hydroxylation of laurate in microsomes from untreated or ω-naphthoflavone-treated trout.
ASJC Scopus subject areas
- Molecular Biology