Demonstration of a new glycopeptidase, from jack-bean meal, acting on aspartylglucosylamine linkages.

An enzyme preparation from jack-bean meal hydrolyzed beta-aspartylglucosylamine linkages in glycopeptides. The enzyme could release sialic acid-containing complex-type oligosaccharides as well as high-mannose-type and hybrid-type oligosaccharides. The products were equimolar amounts of ammonia, oligosaccharide and peptide. The enzyme cleaved glycopeptides with three or more amino acid residues, whereas it did not hydrolyze GlcNAc-Asn. The mechanism of action of the enzyme and substrate specificity so far tested were similar to those of the glycopeptidase from almonds.