title: Regiospecific hydroxylation of lauric acid at the (omega-1) position by hepatic and kidney microsomal cytochromes P-450 from rainbow trout.
abstract: Microsomes from liver or kidney of untreated rainbow trout hydroxylated lauric acid specifically at the (omega-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 beta-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 alpha-naphthoflavone. The temperature optimum of laurate (omega-1) hydroxylation in trout liver microsomes was 25-30 degrees C. The Km and Vmax for (omega-1)- hydroxylaurate formation was 50 microM and 1.63 nmol min-1 mg-1, respectively, in liver and 20 microM and 3.95 nmol min-1 mg-1, respectively, in kidney from untreated trout microsomes. (omega-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 beta-naphthoflavone did not inhibit (omega-1) hydroxylation of laurate in microsomes from untreated or beta-naphthoflavone-treated trout.
mesh_terms: D000818:Animals; D000906:Antibodies; D001571:Benzoflavones / Q000494:pharmacology; D001665:Binding Sites; D019363:Cytochrome P-450 CYP1A1; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology / Q000378:metabolism*; D006900:Hydroxylation; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D007850:Lauric Acids / Q000378:metabolism*; D008861:Microsomes / Q000201:enzymology; D008862:Microsomes, Liver / Q000201:enzymology*; D010088:Oxidoreductases / Q000378:metabolism; D012487:Salmonidae / Q000378:metabolism*; D013696:Temperature; D014337:Trout / Q000378:metabolism*; D019324:beta-Naphthoflavone
chemical_list: D000906:Antibodies; D001571:Benzoflavones; D065607:Cytochrome P-450 Enzyme Inhibitors; D007850:Lauric Acids; C030358:lauric acid; D019324:beta-Naphthoflavone; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1