Open AccessInduction of phytoalexin synthesis in soybean. Stereospecific 3,9‐dihydroxypterocarpan 6a‐hydroxylase from elicitor‐induced soybean cell cultures
Author(s) -
HAGMANN MarieLuise,
HELLER Werner,
GRISEBACH Hans
Publication year - 1984
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1984.tb08259.x
Subject(s) - phytoalexin , elicitor , hydroxylation , stereospecificity , enzyme , chemistry , biosynthesis , biochemistry , stereochemistry , inducer , substrate (aquarium) , biology , catalysis , gene , resveratrol , ecology
A microsomal preparation from elicitor‐challenged soybean cell suspension cultures catalyzes an NADPH‐dependent and dioxygen‐dependent 6a‐hydroxylation of 3,9‐dihydroxypterocarpan to 3,6a,9‐trihydroxypterocarpan. The latter is a precursor for the soybean phytoalexin glyceollin. No reaction is observed with NADH. The 6a‐hydroxylase is inhibited by cytochrome c. Optical rotatory dispersion spectra of the enzymatic product formed from racemic dihydroxypterocarpan and of the remaining unreacted substrate proved that the product has the natural (6a S , 11a S )‐configuration and that hydroxylation proceeds with retention of configuration. The 6a‐hydroxylase was also found in elicitor‐challenged soybean seedlings. The results indicate that the 6a‐hydroxylase is specifically involved in the biosynthesis of glyceollin.