A Cyiochrome P450 Mediated Naringenin 3'-Hydroxylase from Sweet Orange Cell Cultures : PROTEINS, ENZYMES AND METABOLISM : STRUCTURE AND FUNCTION OF CELLS

スポンサーリンク

概要

• 論文の詳細を見る

• A microsomal flavonoid 3'-hydroxylase (F3'H) catalyzing the metabolism of naringenin to eriodictyol in Citrus sinensis (L.) Osbeck cv. 'Hamlin' cell suspension cultures was shown to be a cytochrome P450 enzyme. This reaction required O_2 and NADPH and was inhibited by CO, with partial reversal of CO-inhibition by light at 450 nm. Cytochrome P450 content ranged from 10-20 pmol (mg microsomal protein)^<-1>. The F3'H reaction was shown to be linear in regard to protein concentration between 2.5 and 25 μg of microsomal protein. The optimum pH for the reaction was 7.4-7.6 and the temperature optimum was between 30 and 37℃. The apparent K_m and V_<max> for naringenin were 24 μM ± 3.2 and 81.4 ± 7.9 pmol eriodictyol min^<-1> (mg protein)^<-1>, respectively. The microsomal F3'H was also capable of forming dihydroquercetin from dihydrokaempferol (40 pmol min^<-1> (mg protein)^<-1>) and of quercetin from kaempferol (3.25 pmol min^<-1> (mg protein^<-1>). Cytochrome c and ketoconazole were the best inhibitors of F3'H activity followed by piperonyl butoxide and α-naphthoflavone. Light was shown to be an inducer of the F3'H almost doubling the specific activity and increasing the microsomal cytochrome P450 content by 30% over that of dark grown cells. F3'H activity was also confirmed in microsomal preparations of young (new flush) leaves from 'Hamlin' trees and flavedo of 'Hamlin' oranges, 'Marsh' grapefruit, and 'Lisbon' lemon. No activity was observed in older, hardened leaves and albedo of all the fruit tested. Initiation of embryogenesis in the 'Hamlin' cell suspension cultures by switching from a sucrose medium to a glycerol-based medium resulted in the down-regulation of F3'H.

• 日本植物生理学会の論文

著者

• Mayer Richard

  U.s. Department Of Agriculture Agricultural Research Service U.s. Horticultural Research Laboratory

• Doostdar Hamed

  U.s. Department Of Agriculture Agricultural Research Service U.s. Horticultural Research Laboratory

• Shapiro Jeffrey

  U.s. Department Of Agriculture Agricultural Research Service U.s. Horticultural Research Laboratory

• NIEDZ Randall

  U.S. Department of Agriculture, Agricultural Research Service, U.S. Horticultural Research Laborator

• BURKE M.D.

  University of Aberdeen, Department of Biomedical Sciences, Marischal College

• MC-COLLUM T.Gregory

  U.S. Department of Agriculture, Agricultural Research Service, U.S. Horticultural Research Laborator

• MCDONALD Roy

  U.S. Department of Agriculture, Agricultural Research Service, U.S. Horticultural Research Laborator

• Mcdonald Roy

  U.s. Department Of Agriculture Agricultural Research Service U.s. Horticultural Research Laboratory

• Niedz Randall

  U.s. Department Of Agriculture Agricultural Research Service U.s. Horticultural Research Laboratory

• Mc-collum T.gregory

  U.s. Department Of Agriculture Agricultural Research Service U.s. Horticultural Research Laboratory

• Burke M.d.

  University Of Aberdeen Department Of Biomedical Sciences Marischal College

関連論文

• A Cyiochrome P450 Mediated Naringenin 3'-Hydroxylase from Sweet Orange Cell Cultures : PROTEINS, ENZYMES AND METABOLISM : STRUCTURE AND FUNCTION OF CELLS
• Identification and Characterization of Acidic Hydrolases with Chitinase and Chitosanase Activities from Sweet Orange Callus Tissue : PROTEINS, ENZYMES AND METABOLISM : STRUCTURE AND FUNCTION OF CELLS

スポンサーリンク