Studies on the hexosaminidases from concanavalin A-resistant and sensitive cell lines : A model system for the study of secretion and uptake of lysosomal enzymes

Parental wild-type and concanavalin A (ConA)-resistant Chinese hamster ovary cells (C^R-7) grown in suspension and on the surface of glass culture bottles were analysed for intracellular and extracellular hexosaminidase forms. When intracellular enzymes were examined three forms were identified (designated Hex I, II and III) depending on the conditions used to elute the enzymes from DEAE-cellulose columns. Only Hex I and III were detected in the medium of the cultured cells suggesting that Hex II is not secreted. Several differences in intracellular and extracellular levels of hexosaminidases were found between C^R-7 and parental wild-type cells which are explained by postulating that there is a difference in the relative abilities of these cells to internalize the hexosaminidase forms. This view is supported by results obtained from previous biochemical experiments carried out with these cell lines.