Affinity chromatography of branched oligosaccharides in rat liver beta-glucuronidase

Rat liver microsomal and lysosomal beta -glucuronidase-derived glycopeptide s were obtained by extensive Pronase digestion followed by N-[C-14]acetylat ion and desialylation by neuraminidase treatment. These glycopeptides were studied by sequential chromatography on lectin-affinity columns such as con canavalin A, lentil lectin, Phaseolus vulgaris erythroagglutinin, Ricinus c ommunis agglutinin I, Triticum vulgaris agglutinin, Glycine max agglutinin and Ulex europaeus agglutinin. Using serial lectin affinity chromatography approach combined with neuraminidase treatment allowed us to show the unexp ected presence of complex tri- and/or tetraantennary type glycans (40.8 and 17.0% for microsomal and lysosomal enzyme, respectively). Moreover, the ap plication of neuraminidase treatment revealed that complex biantennary type glycans, present on lysosomal beta -glucuronidase, are almost fully sialyl ated while the same type of glycans present on microsomal enzyme do not con tain sialic acid. Furthermore, the results obtained confirmed that microsom al and lysosomal beta -glucuronidases possess high mannose and/or hybrid ty pe glycans (19.6 and 36.6%, respectively), and complex biantennary type gly cans (38.9 and 46.4%, respectively). (C) 2001 Elsevier Science B.V. All rig hts reserved.