XYLAN SYNTHESIS FROM URIDINE-DIPHOSPHATE-D-XYLOSE BY PARTICULATE PREPARATIONS FROM IMMATURE CORNCOBS

Abstract

Particulate preparations from immature corncobs contain enzymes which catalyze the epimerization of UDP-D-xylose-C14 to UDP-L-ara-binose-C14 and the transfer of the sugars from both of these sugar nucleotides to polysaccharide. The synthetic polysaccharide is similar to natural corn xylan as it is soluble in alkali and contains acid-labile L-arabinofuranosyl units and chains of 1,4-linked xylosyl units which have a [beta]-configuration. The xylan-synthesizing activity of-the particulate preparation is considerable enhanced by preparation and assay in the presence of 1% bovine serum albumin and 0.4 [image] sucrose and is depressed by UTP, UDP, UMP, GMP, and AMP, but not by uridine ATP, or GTP.