Further studies on endo-beta-N-acetylglucosaminidase D1

The purification procedure for endo-beta-N-acetylglucosaminidase D was improved to yield an enzyme preparation which was homogeneous upon gel electrophoresis. The molecular weight of the enzyme as estimated by Sephadex G-200 column chromatography was 280,000, while SDS-gel electrophoresis after reduction with 2-mercaptoethanol gave a value of 150,000. The purified enzyme did not show any chitinase, hyaluronidase or lysozyme activity. In the presence of exoglycosidases removing peripheral sugars, the endoglycosidase acted on serum glycoproteins such as transferrin and fetuin. The enzyme also hydrolyzed an oligosaccharide, (Man)5(GlcNAc)2, indicating that the peptide portion of substrates does not have much effect on susceptibility to the enzyme.