| Popis: |
Ovotransferrin (POT), two ovalbumins (POA(hi) and POA(lo)), and ovomucoid (POM) were isolated from pigeon egg white (PEW). Unlike their chicken egg white counterparts, PEW glycoproteins contain terminal Galα1–4Gal, as evidenced by GS-I lectin (specific for terminal α-Gal), anti-P1(Galα1–4Galβ1–4GlcNAcβ1–3Galβ1–4Glcβ1–1Cer) monoclonal antibody, and P fimbriae on uropathogenic Escherichia coli(specific for Galα1–4Gal). Galα1–4Gal on PEW glycoproteins were found in N-glycans releasable by treatment with glycoamidase F. The respective contents of N-glycans in each glycoprotein were 3.5%, POT; 17%, POA(hi); and 31–37%, POM. POA(hi) has four N-glycosylation sites, in contrast to chicken ovalbumin, which has only one. High performance liquid chromatography analysis showed that N-glycans on POA(hi) were highly heterogeneous. Mass spectrometric analysis revealed that the major N-glycans were monosialylated tri-, tetra-, and penta-antennary oligosaccharides containing terminal Galα1–4Gal with or without bisecting N-acetylglucosamine. Oligosaccharide chains terminating in Galα1–4Gal are rare amongN-glycans from the mammals and avians that have been studied, and our finding is the first predominant presence of (Galα1–4Gal)-terminated N-glycans. |
