Susceptibility to neuraminidase of alpha-L-fucosidase and N-acetyl-beta-D-glucosaminidase of cystic fibrosis, I-cell and neuraminidase-deficient fibroblasts.

Intracellular alpha-L-fucosidase and hexosaminidase showed similar isoelectro-focusing patterns in control, cystic fibrosis and neuraminidase-deficient fibroblasts and were unaffected by neuraminidase treatment. An I-cell strain excreted these two enzymes at 3-4 times the rate of the three other cell types. I-cell and neuraminidase-deficient cells excreted more of the electronegative forms of these enzymes than control and cystic fibrosis cells. Extracellular hexosaminidase A and B were both sensitive to neuraminidase for the four cell types. Extracellular alpha-L-fucosidase consisted of a pH 6.1 form insensitive to neuraminidase and other forms that were sensitive and changed to a pI 7.0-7.1 form. Cystic fibrosis extracellular alpha-L-fucosidase and hexosaminidase behaved as for control fibroblasts.