Differential inactivation of plant lauric acid omega- and in-chain-hydroxylases by terminally unsaturated fatty acids.
The microsomal fraction from Vicia sativa L. cv. Septimane contains a cytochrome P-450-dependent lauric acid omega-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 X 10(-3) s-1. In contrast, the olefinic analog 11-dodecenoic acid is primarily a time-independent inhibitor of the omega-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 omega-hydroxylase. Conversely, cinnamic acid 4-hydroxylase is only slightly affected by concentrations of 11-dodecynoic acid that completely inactivate the omega-hydroxylase. 11-Dodecynoic acid is thus a potent, relatively specific, inactivator of the V. sativa lauric acid omega-hydroxylase.
Salaün
J P
JP
Laboratoire d'Enzymologie Cellulaire et Moleculaire, Université Louis Pasteur, CNRS UA 1182, Strasbourg, France.
Simon
A
A
Durst
F
F
Reich
N O
NO
Ortiz de Montellano
P R
PR
D002994:Clofibrate / Q000494:pharmacology; D042926:Cytochrome P-450 CYP4A; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D007887:Fabaceae; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D009249:NADP / Q000494:pharmacology; D010944:Plants / Q000201:enzymology*; D010946:Plants, Medicinal; D050564:Trans-Cinnamate 4-Monooxygenase
D065607:Cytochrome P-450 Enzyme Inhibitors; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; C040948:11-dodecynoic acid; C054728:11-dodecenoic acid; D009249:NADP; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D050564:Trans-Cinnamate 4-Monooxygenase; D042926:Cytochrome P-450 CYP4A; D002994:Clofibrate