Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Cryptoregiochemistry of a Brassica napus fatty acid desaturase (FAD3): a kinetic isotope effect study
Autore:
Savile, CK; Reed, DW; Meesapyodsuk, D; Covello, PS; Buist, PH;
Indirizzi:
Natl Res Council Canada, Inst Plant Biotechnol, Saskatoon, SK S7N 0W9, Canada Natl Res Council Canada Saskatoon SK Canada S7N 0W9 n, SK S7N 0W9, Canada Carleton Univ, Ottawa Carleton Chem Inst, Dept Chem, Ottawa, ON K1S 5B6, Canada Carleton Univ Ottawa ON Canada K1S 5B6 t Chem, Ottawa, ON K1S 5B6, Canada
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1
fascicolo: 9, , anno: 2001,
pagine: 1116 - 1121
SICI:
1472-7781(2001):9<1116:COABNF>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
LITTORALIS SEX-PHEROMONE; SACCHAROMYCES-CEREVISIAE; DOUBLE-BOND; SUBSTRATE-SPECIFICITY; LIPID-METABOLISM; HYDROXYLATION; BIOSYNTHESIS; ENZYMES; MONOOXYGENASE; DERIVATIVES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Covello, PS Natl Res Council Canada, Inst Plant Biotechnol, 110 Gymnasium Rd, Saskatoon, SK S7N 0W9, Canada Natl Res Council Canada 110 Gymnasium Rd Saskatoon SK Canada S7N 0W9
Citazione:
C.K. Savile et al., "Cryptoregiochemistry of a Brassica napus fatty acid desaturase (FAD3): a kinetic isotope effect study", J CHEM S P1, (9), 2001, pp. 1116-1121

Abstract

alpha -Linolenic acid ((Z,Z,Z)-octadeca-9,12,15-trienoic acid) is biosynthesized by a series of regio- and stereoselective dehydrogenation reactions which are catalyzed by a set of enzymes known as fatty acid desaturases. Aspart of ongoing research into the mechanism of these remarkable catalysts,we have examined the cryptoregiochemistry (site of initial oxidation) of extraplastidial omega -3 desaturation as it occurs in the commercially important plant Brassica napus (oilseed rape or canola). The individual deuterium kinetic isotope effects associated with the C-H bond cleavages at C-15 and C-16 of a thiaoleoyl analogue were measured using a convenient in vivo yeast expression system. Competition experiments using appropriately deuterium-labelled 7-thia substrates revealed a large kinetic isotope effect (KIE) (k(H)/k(D)=7.5 +/-0.4) for the C-H bond-breaking step at C-15 while the C-Hbond cleavage at C-16 was found to be insensitive to deuterium substitution (k(H)/k(D)=1.0 +/-0.14). These results point to C-15 as the site of initial oxidation in omega -3 desaturation since the first chemical step in thistype of reaction is rupture of a strong, unactivated C-H bond-an energetically difficult process which typically exhibits a large KIE.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/04/20 alle ore 07:52:16