The Biosynthesis of Cyanogenic Glucosides in Higher Plants IDENTIFICATION OF THREE HYDROXYLATION STEPS IN THE BIOSYNTHESIS OF DHURRIN IN SORGHUM BICOLOR (L.) MOENCH AND THE INVOLVEMENT
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چکیده
s of the 11th Federation of European Biochemical Societies Meeting, Copenhagen, August 14-19, 1977, Abstr. LB-400. by gest on O cber 8, 2017 hp://w w w .jb.org/ D ow nladed from 21116 Biosynthesis of the Cyanogenic Glucoside Dhurrin in Sorghum FIG. 1. Biosynthetic pathway for tyrosine-derived cyanogenic glucoside dhurrin from S. bicolor. The double arrows indicate potential multistep conversions. CkFH-COOH v HOj-$H&H-COOH HO~CH&H * NY \--/ ‘N-OH \--/ I;IH
منابع مشابه
The biosynthesis of cyanogenic glucosides in higher plants. N-Hydroxytyrosine as an intermediate in the biosynthesis of dhurrin by Sorghum bicolor (Linn) Moench.
The following compounds were tested as early intermediates in the conversion of tyrosine to p-hydroxymandelonitrile by a microsomal preparation from dark grown sorghum seedlings: p-hydroxyphenylacetamide, 1-nitro-2-p-hydroxyphenylethane, p-hydroxyphenyl-pyruvic acid oxime, tyramine, N-hydroxytyramine, and N-hydroxytyrosine. Of these, only N-hydroxytyrosine was metabolized to p-hydroxymandelonit...
متن کاملInvolvement of Cytochrome P-450 in the Biosynthesis of Dhurrin in Sorghum bicolor (L.) Moench.
The biosynthesis of the tyrosine-derived cyanogenic glucoside dhurrin involves N-hydroxytyrosine, (E)- and (Z)-p-hydroxyphenylacetaldehyde oxime, p-hydroxyphenylacetonitrile, and p-hydroxymandelonitrile as intermediates and has been studied in vitro using a microsomal enzyme system obtained from etiolated sorghum (Sorghum bicolor [L.] Moench) seedlings. The biosynthesis is inhibited by carbon m...
متن کاملStereochemical aspects of the biosynthesis of the epimeric cyanogenic glucosides dhurrin and taxiphyllin.
Dhurrin, I ((S)-p-hydroxymandelonitrile-beta-D-glucopyranoside), and taxiphyllin, II (the (R) epimer), occur in the genera Sorghum and Taxus, respectively. Both derive biosynthetically from L-tyrosine via the hydroxylation of p-hydroxyphenylacetonitrile, III. (3R)- and (3S)-L-[3-3H1]tyrosine, prepared by enzymic hydroxylation of the corresponding phenylalanines, were fed separately to shoots fr...
متن کاملThe in vitro biosynthesis of dhurrin, the cyanogenic glycoside of Sorghum bicolor.
A microsomal fraction from seedlings of Sorghum bicolor (Linn) Moench has been shown to catalyze the conversion of L-tyrosine to p-hydroxymandelonitrile via p-hydroxyphenylacetaldoxime. This transformation is consistent with the general pathway for cyanogenic glycoside biosynthesis proposed on the basis of in vivo experiments. When the microsomal fraction was combined with a protein fraction fr...
متن کاملTransgenic tobacco and Arabidopsis plants expressing the two multifunctional sorghum cytochrome P450 enzymes, CYP79A1 and CYP71E1, are cyanogenic and accumulate metabolites derived from intermediates in Dhurrin biosynthesis.
Novel cyanogenic plants have been generated by the simultaneous expression of the two multifunctional sorghum (Sorghum bicolor [L.] Moench) cytochrome P450 enzymes CYP79A1 and CYP71E1 in tobacco (Nicotiana tabacum cv Xanthi) and Arabidopsis under the regulation of the constitutive 35S promoter. CYP79A1 and CYP71E1 catalyze the conversion of the parent amino acid tyrosine to p-hydroxymandelonitr...
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تاریخ انتشار 2001