Bhavanandan VP, Codington JF. Selective release of the disaccharide 2-acetamido-2-deoxy-3-O-(beta-D-galactopyranosyl)-D-galactose from epiglycanin by endo-N-acetyl-alpha-D-galactosaminidase.
Carbohydr Res 1983;
118:81-9. [PMID:
6311416 DOI:
10.1016/0008-6215(83)88037-9]
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Abstract
Epiglycanin, the major glycoprotein of TA3-Ha mammary carcinoma ascites cells, was radiolabeled with tritium in the terminal D-galactose and 2-acetamido-2-deoxy-D-galactose residues. Alkaline-borohydride treatment, reported to release five O-glycosyl-linked chain types from epiglycanin, resulted in the cleavage of 98-99% of the radioactivity from the protein. Of this, 63% of the radioactivity from epiglycanin and 70% from asialoepiglycanin co-migrated with an authentic sample of 2-acetamido-2-deoxy-3-O-(beta-D-galactopyranosyl)-D-galactitol on a column of Bio-Gel P-6. Incubation of [3H]galactose-epiglycanin with endo-N-acetyl -alpha-D-galactosaminidase (Diplococcus pneumoniae), and fractionation of the mixture on a column of Bio-Gel P-4, gave only one oligosaccharide peak containing 62 and 70%, respectively, of the radioactivity of epiglycanin and asialoepiglycanin. This oligosaccharide comigrated with authentic 2-acetamido-2-deoxy-3-O-(beta-D-galactopyranosyl)-D-galactose (1) on columns of Bio-Gel P-2 and P-4 and on paper chromatograms. Results of experiments in which unlabeled epiglycanin was treated with enzyme and the products analyzed, by three different methods, suggested that 78-85% of 1 had been cleaved. Another enzyme, N-acetyl-alpha-D-galactosaminyl-oligosaccharidase from Clostridium perfringens, exhibited similar specificity and cleaved 65% of the radioactivity from ([3H]galactose)asialoepiglycanin, which was eluted from a Bio-Gel P-2 column as the disaccharide 1.
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