Partial Purification & Properties of Xylose & Ribose Isomerase in Higher Plants

Abstract

The conversion of L-arabinose into the pentose moieties of plant polysaccharides proceeds wvith lit- tle rearrangement of the carbon skeleton (14,18). On the other hand D-ribose and D-xylose suffer con- siderable rearrangement. Experiments with specifically labeled sugars suggest that these twvo pentoses must pass through a hexose and indeed through the pentose phosphate pathway The discovery by Hassid and his co-workers of L- arabinose kinase and the appropriate pyrophosphorylases and sugar nucleotide epimerases readily ac- counts for the observations with L-arabinose (19). However kinases for D-ribose and D-xylose have not been found in higher plants.