The glycoprotein nature and antigenicity of a fungal D-glucosyltransferase.

D-Glucosyltransferase (EC 2.4.1.24) from Aspergillus niger has been prepared in pure form by chromatography on DEAE-cellulose. The enzyme transfers D-glucosyl units from maltose and other alpha-linked D-glucosyl oligosaccharides to glucosyl co-substrates resulting in the synthesis of new types of oligosaccharides. The glucosyltransferase has been found to be a glycoprotein containing 20% of carbohydrate consisting of mannose, glucose, and galactose. The carbohydrate residues are attached as either single units or as short oligosaccharide chains by O-glycosyl linkages to the serine and threonine residues of the protein. Antibodies directed against glucosyltransferase have been induced in animals by appropriate immunization regimes. These antibodies combine with the carbohydrate components of the enzyme and, therefore, the carbohydrate residues are the immunodeterminant groups of the glucosyltransferase.