Differential inactivation of plant lauric acid ω- and in-chain-hydroxylases by terminally unsaturated fatty acids

• Published in: Archives of biochemistry and biophysics Vol. 260; no. 2; pp. 540 - 545
• Main Authors: Salaün, Jean-Pierre, Simon, Annick, Durst, Francis, Reich, Norbert O., De Montellano, Paul R.Ortiz
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.02.1988; Elsevier
• Subjects: ACIDE GRAS; ACIDE LAURIQUE; ACIDO LAURICO; ACIDOS GRASOS; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Clofibrate - pharmacology; Cytochrome P-450 CYP4A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System - metabolism; Enzyme Induction - drug effects; ENZYME INHIBITORS; Fabaceae; FATTY ACIDS; Fatty Acids, Monounsaturated - pharmacology; Fatty Acids, Unsaturated - pharmacology; Fundamental and applied biological sciences. Psychology; GRAINE; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; Kinetics; LAURIC ACID; Lipids; Microsomes - enzymology; Mixed Function Oxygenases - antagonists & inhibitors; Mixed Function Oxygenases - biosynthesis; NADP - pharmacology; Other biological molecules; OXIDOREDUCTASES; OXIDORREDUCTASAS; OXYDOREDUCTASE; Plants - enzymology; Plants, Medicinal; SEEDS; SEMILLA; Trans-Cinnamate 4-Monooxygenase; VICIA SATIVA
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/0003-9861(88)90479-1

The microsomal fraction from Vicia sativa L. cv. Septimane contains a cytochrome P-450-dependent lauric acid ω-hydroxylase that is inactivated in a time-dependent, pseudo-first-order manner when the microsomes are incubated with 11-dodecynoic acid. The rate constant for the inactivation is approximately 4.3–4.8 × 10 −3 s −1. In contrast, the olefinic analog 11-dodecenoic acid is primarily a time-independent inhibitor of the ω-hydroxylase. 1-Aminobenzotriazole, 3-phenoxy-1-propyne, and 3-(2,4-dichlorophenoxy)-1-propyne, mechanism-based inactivators of cinnamic acid 4-hydroxylase, and 9-decenoic acid, a mechanism-based inactivator of the lauric acid in-chain hydroxylase, are at best poor inactivators of the ω-hydroxylase. Conversely, cinnamic acid 4-hydroxylase is only slightly affected by concentrations of 11-dodecynoic acid that completely inactivate the ω-hydroxylase. 11-Dodecynoic acid is thus a potent, relatively specific, inactivator of the V. sativa lauric acid ω-hydroxylase.