CYP94A5, a new cytochrome P450 from Nicotiana tabacum is able to catalyze the oxidation of fatty acids to the omega-alcohol and to the corresponding diacid.
Eur J Biochem
; 268(10): 3083-90, 2001 May.
Article
em En
| MEDLINE
| ID: mdl-11358528
ABSTRACT
A full length cDNA encoding a new cytochrome P450-dependent fatty acid hydroxylase (CYP94A5) was isolated from a tobacco cDNA library. CYP94A5 was expressed in S. cerevisiae strain WAT11 containing a P450 reductase from Arabidopsis thaliana necessary for catalytic activity of cytochrome P450 enzymes. When incubated for 10 min in presence of NADPH with microsomes of recombinant yeast, 9,10-epoxystearic acid was converted into one major metabolite identified by GC/MS as 18-hydroxy-9,10-epoxystearic acid. The kinetic parameters of the reaction were Km,app = 0.9 +/- 0.2 microM and Vmax,app = 27 +/- 1 nmol x min(-1) x nmol(-1) P450. Increasing the incubation time to 1 h led to the formation of a compound identified by GC/MS as 9,10-epoxy-octadecan-1,18-dioic acid. The diacid was also produced in microsomal incubations of 18-hydroxy-9,10-epoxystearic acid. Metabolites were not produced in incubations with microsomes of yeast transformed with a control plasmid lacking CYP94A5 and their production was inhibited by antibodies raised against the P450 reductase, demonstrating the involvement of CYP94A5 in the reactions. The present study describes a cytochrome P450 able to catalyze the complete set of reactions oxidizing a terminal methyl group to the corresponding carboxyl. This new fatty acid hydroxylase is enantioselective after incubation of a synthetic racemic mixture of 9,10-epoxystearic acid, the chirality of the residual epoxide was 40/60 in favor of 9R,10S enantiomer. CYP94A5 also catalyzed the omega-hydroxylation of saturated and unsaturated fatty acids with aliphatic chain ranging from C12 to C18.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxigênio
/
Plantas Tóxicas
/
Nicotiana
/
Sistema Enzimático do Citocromo P-450
/
Ácidos Graxos
/
Oxigenases de Função Mista
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Eur J Biochem
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
França