Almond glycopeptidase acting on aspartylglycosylamine linkages. Multiplicity and substrate specificity

Abstract

The glycopeptidase preparation that has been isolated from almond emulsin and acts on beta-aspartylglycosylamine linkages in glycopeptides was separated into three active fractions by DEAE-cellulose column chromatography. The three discrete species of glycopeptidase (Groups A, B and C) have been purified 30-, 136-, and 99-fold, respectively. The optimum pH value of Group A was 6.0 and those of Groups B and C, 5.0. Isoelectric points of Groups A, B and C were pH 7.7, 8.6 and 8.7, respectively. All three glycopeptidases hydrolyzed quantitatively glycopeptides with 3-11 amino acid residues prepared from stem bromelain, ovalbumin and ovotransferrin. Group C preferred glycopeptides with shorter peptide chains, whereas Groups A and B preferred those with longer chains. Glycopeptidase Group A also hydrolyzed intact glycoproteins such as stem bromelain, ovalbumin, Taka-amylase A and desialylated human transferrin.