Purification and Properties of an Endo-β-N-acetylglucosaminidase from Streptomyces griseus

Abstract

Abstract An enzyme that hydrolyzes di-N-acetylchitobiose linkages in oligosaccharides and glycoproteins was purified to homogeneity from cultural filtrates of Streptomyces griseus. The molecular weight of the enzyme, determined by sedimentation equilibrium analysis, is 27,200 ± 200, and it appears to consist of a single polypeptide chain. This apparent endo-β-N-acetylglucosaminidase was completely stable at 37° for at least 48 hours and resistant to inactivation by several proteolytic enzymes. Treatment of Asn-(GlcNAc)2(Man)6, Asn-(GlcNAc)2(Man)6(GlcNAc)2, and (GlcNAc)2(Man)6(Glc-NAc)2 with the enzyme yielded Asn-GlcNAc + (GlcNAc)1-(Man)6, Asn-GlcNAc + (GlcNAc)1(Man)6(GlcNAc)2, and GlcNAc + (GlcNAc)1(Man)6(GlcNAc)2, respectively. The [3H]dansyl-Asn derivatives, which were rapidly hydrolyzed also, were used as substrates to assay the enzyme. Similar findings obtained with specific glycoproteins are described in the accompanying paper (Tarentino, A. L., Plummer, T. H., Jr., and Maley, F. (1974) J. Biol. Chem. 249, 818–824). Asn-(GlcNAc)2(Man)1 was not hydrolyzed by this enzyme but was hydrolyzed by another apparent endo-β-N-acetyl-glucosaminidase. The latter could be separated from the Asn-(GlcNAc)2(Man)6 hydrolyzing endoglycosidase by Sephadex G-100 chromatography.