title: Elicitor induction of a microsomal 5-O-(4-coumaroyl)shikimate 3'-hydroxylase in parsley cell suspension cultures.
abstract: Microsomal preparations from parsley cell suspension cultures challenged with an elicitor from Phytophthora megasperma f.sp. glycinea (Pmg) catalyze the formation of trans-5-O-caffeoylshikimate from trans-5-O-(4-coumaroyl)shikimate. Neither the cis isomer nor free 4-coumarate, 4-coumaroyl-CoA, or 5-O-(4-coumaroyl)quinate are substrates for this enzyme. The reaction is strictly dependent on NADPH as a reducing cofactor and on molecular oxygen. NADH, ascorbic acid, and 6,7-dimethyl-5,6,7,8-tetrahydropterine cannot substitute for NADPH. However, NADH enhances enzyme activity observed in the presence of NADPH. Cytochrome c and carbon monoxide inhibit the hydroxylation reaction, suggesting a cytochrome P-450-dependent mixed-function monooxygenase.
mesh_terms: D002110:Caffeine / Q000378:metabolism; D002478:Cells, Cultured; D004790:Enzyme Induction; D006863:Hydrogen-Ion Concentration; D008861:Microsomes / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D009249:NADP / Q000494:pharmacology; D010100:Oxygen / Q000494:pharmacology; D010944:Plants / Q000201:enzymology*; D013379:Substrate Specificity; D013535:Suspensions
chemical_list: D013535:Suspensions; D002110:Caffeine; D009249:NADP; D006899:Mixed Function Oxygenases; C046562:5-O-(4-coumaroyl)shikimate 3'-hydroxylase; D010100:Oxygen