SEPARATION OF N-ACETYL-ALPHA-GLUCOSAMINIDASE AND N-ACETYL-ALPHA-GALACTOSAMINIDASE FROM OX SPLEEN - CLEAVAGE OF O-GLYCOSIDIC LINKAGE BETWEEN CARBOHYDRATE AND POLYPEPTIDE IN OVINE AND BOVINE SUBMAXILLARY GLYCOPROTEIN BY N-ACETYL-ALPHA-GALACTOSAMINIDASE

Two specific N‐acetyl‐α‐hexosaminidases were detected in bovine spleen homogenates, purified by ammonium sulphate precipitation, separated by gel filtration and identified as N‐acetyl‐α‐glucosaminidase and N‐acetyl‐α‐galactosaminidase respectively. In contrast to the established N‐acetyl‐β‐hexosaminidase which splits phenyl‐β‐d‐glycosides of both N‐acetyl‐glucosamine and N‐acetylgalactosamine, the two N‐acetyl‐α‐hexosaminidases exhibits an absolute specificity towards the hexosamine moiety of their substrates. N‐Acetyl‐α‐galactosaminidase acts on phenyl‐N‐acetyl‐α‐d‐galactosaminide and not on the corresponding glucosaminide. The reverse holds for N‐acetyl‐α‐glucosaminidase. In the cell‐free supernatant of a bovine spleen homogenate N‐acetyl‐α‐galactosaminidase is present with a specific activity about 50‐fold of that of the corresponding glucosaminidase, using the appropriate phenyl‐α‐d‐hexosaminides as substrate. Ox spleen N‐acetyl‐α‐galactosaminidase was found to split both phenyl‐N‐acetyl‐α‐d‐galactosaminide and the O‐glycosidic linkage between terminal N‐acetylgalactosamine and peptide‐bonded serine (threonine) in ovine and bovine submaxillary glycoproteins. The identity of bovine O‐seryl‐N‐acetylgalactosaminide glycosidase and N‐acetyl‐α‐galactosaminidase is clearly demonstrated by the presence of these enzymatic activities in a single chromatographic peak even after re‐chromatography. One substrate of natural origin for N‐acetyl‐α‐glucosaminidase was found in UDP‐N‐acetylglucosamine. Copyright © 1969, Wiley Blackwell. All rights reserved