Change in activities of lysosomal glycosidases in skin fibroblasts from controls and patients with cystic fibrosis
Hermelin, B.; Bertrand, F.; Blivet, M.J.; Picard, J.
Cellular and Molecular Biology 33(1): 83-89
1987
ISSN/ISBN: 0145-5680 PMID: 2952277 Document Number: 303452
Intracellular activities of 3 lysosomal enzymes (.alpha.-L-fucosidase, .alpha.-mannosidase and .beta.-N acetylhexosaminidase) of skin fibroblast cultures showed significant variations during the cell growth from both control subjects and cystic fibrosis patients. Under the effect of chloroquine, a lysosomotropic agent, these lysosomal enzyme activities decrease with a corresponding increase in culture media. Whereas the reduction in the activity of .beta.-N acetylhexosaminidase in normal fibroblasts is due only to a modification in the A isoenzyme form, in cystic fibrosis fibroblasts both A and B isoenzymes are affected. The analysis of kinetic constants for both A and B isoenzymes shows that in cystic fibrosis fibroblasts the maximum velocity (Vmax) of the A isoenzyme is not modified while that of the B isoenzyme is markedly increased (on the order of 50%). These findings suggest an anomaly in the B isoenzyme form of .beta.-N acetylhexosaminidase in skin fibroblasts from patients with cystic fibrosis.