Glucosinolate Biosynthesis: Sulfation of Desulfobenzylglucosinolate by Cell-Free Extracts of Cress (Lepidium sativum L.) Seedlings.
After removal of myrosinase activity by concanavalin A-Sepharose 4B chromatography, cell-free extracts of light-grown cress (Lepidium sativum L.) seedlings, catalyzed the sulfation of desulfobenzylglucosinolate (K(m), 0.23 millimolar) to benzylglucosinolate using PAPS (K(m), 1 millimolar) as sulfur donor. Sulfotransferase activity, which was optimal at pH 9.0, was stimulated by MgCl(2), MnCl(2), beta-mercaptoethanol, and dithiothreitol and was inhibited by ZnSO(4) and SH-reagents. The enzyme also sulfated desulfoallyglucosinolate to allylglucosinolate (sinigrin) but was inactive towards all phenylpropanoids and flavonoids tested.
Glendening
T M
TM
Department of Botany, University of Iowa, Iowa City, Iowa 52242.
Poulton
J E
JE