SUBSTRATE SPECIFITY IN THE BIOSYNTHESIS OF CYCLOPENTANOID CYANOHYDRIN GLUCOSIDES

Article abstract of DOI:10.1016/0031-9422(92)80427-G

The biosynthesis of deidaclin in Turnera angustifolia and of linamarin in Passiflora morifolia were investigated using intact plant tissues.Radiolabelled precursors, 2-(2'-cyclopentenyl)<2-14C>glycine and L--valine were fed to freshly harvested shoots either alone or together with the presumed nitrile intermediates, 2-cyclopentenecarbonitrile and 2-methylpropanenitrile.The cyanohydrin glucosides were isolated and purified, and the incorporation of the radioactive labels was determined after enzymatic degradation of the glucosides to cyanide.The labels from the amino acid precursors were incorporated into the nitrile group of their corresponding cyanohydrin glucosides, and the incorporation was in each case strongly inhibited by simultaneous feeding with either of the two nitriles.Turnera angustifolia was able to synthesize linamarin when fed with 2-methylpropanenitrile, even though linamarin could not be demonstrated to be present in this plant naturally. Key Word Index - Passiflora morifolia; Passifloraceae; Turnera angustifolia; Turneraceae; cyanohydrin glucosides; radiolabelling; deidaclin; tetraphyllin A; linamarin; lotaustralin; epilotaustralin; 2-(2'-cyclopentenyl)glycine; 2-cyclopentenecarbonitrile; 2-methylpropanenitrile.