GLUCOSYLTRANSFERASE ISOZYMES IN ALGAE .3. POLYGLUCOSIDE AND ENZYMES OF CYANIDIUM CALDARIUM

Cyanidium caldarium forms a type of storage polyglucoside which resembles that of blue-green and red algae. The storage sugar is a branched polymer of glucose which shows a higher degree of branching than plant amylopectin. Separation of the polyglucoside-synthesizing enzymes of this enigmatic alga on polyacrylamide gel reveals the presence of one phosphorylase, two nucleotide-glucosyltransferase isozymes and two branching isozymes other than Q enzyme. Though the enzyme pattern of the alga has certain similarities to the general distribution of these isozymes in both blue-green and red algae, the mode of action of the branching isozymes, together with the type of storage sugar formed, suggests that the taxonomic classification may fit more appropriately in the Cyanophycean niche. © 1970.