Purification and characterization of two glycopeptide hydrolases from jack beans.

摘要: Two glycopeptide hydrolases, an endo-beta-N-acetylglucosaminidase and peptide:N-glycanase (amidase), have been isolated from defatted jack bean meal by standard procedures involving differential solubility column chromatography. The purified products appear to be free of contaminating proteases exoglycosidases, their substrate specificity has explored with regard both glycan peptide structure the substrates. endoglycosidase appears specific for high mannose glycans; no hydrolysis either hybrid or complex glycans observed. It shows limited activity two intact glycoproteins, ribonuclease B yeast invertase, gives optimal rate glycopeptides. Free glycan-Asn derivatives are poor substrates in comparison glycopeptides where alpha-amino group dansylated. amidase will liberate mannose, hybrid, asialo-complex proteins peptides, but many long peptides resistant become active as only after further proteolytic cleavage. best those glycosylated asparagine more than 4-5 residues NH2- COOH-terminal end peptide. Sialylated do not released amidase.