The nature of lysosomal enzyme glycosylation in ALL: relevance to abnormal beta-hexosaminidase expression.

The glycosylation of beta-hexosaminidase was investigated in the transformed cell-line, CCRF/CEM, derived from a human acute lymphoblastic leukaemia, and comparisons were made with enzyme from normal human skin fibroblasts. A series of studies including neuraminidase sensitivity, lectin chromatography, Biogel P4 chromatography of [3H]-mannose-labelled glycopeptides and endoglycosidase susceptibility, provided clear evidence that in CCRF/CEM cells, beta-hexosaminidase was abnormally glycosylated. The results indicate that leukemia-associated changes in beta-hexosaminidase expression are probably due to increased sialylation of highly-branched complex oligosaccharides.