Changes in glycosidase activities in lectin resistant myogenesis-defective myoblast cell lines

1. Mannosidase, hexosaminidase, galactosidase and fucosidase activities were determined in cell free extracts of wild type and con A-resistant L6 myoblast cells. 2. Two mannosidase activities were detected, with pH optima of 4.6 and 6.0. The con A-resistant cells were almost devoid of intracellular mannosidase activity with optimum pH 4.6. Differences in Km and Vmax values for mannosidase activities were found when con A-resistant and wild type cells were compared. 3. A decrease in the intracellular hexosaminidase activity in the con A-resistant myoblasts was accompanied by an increase in extracellular activity. No differences were observed in the extracellular mannosidase activities of wild type and con A-resistant cells.