Primary amniotic fluid cell, skin fibroblast and liver alpha-L-fucosidase and its relation to cystic fibrosis.

Cultured skin fibroblast and primary amniotic fluid cell alpha-L-fucosidase had a double optimum of pH 5.0 and 6.0. Alpha-L-fucosidase was largely bound as a single peak to DEAE-cellulose at pH 6.6. Sucrose density isoelectric focusing revealed up to seven components with pI values of 4.9, 5.2, 5.4, 5.8, 6.1, 6.5 and 7.1 with their apparent KM values (77--500 mumol/l) being higher than that (57 mumol/l) of the unfocused enzyme. Liver, skin fibroblast and amniotic fluid cell alpha-L-fucosidase was separated into two peaks by gel filtration. Peak one was more active and stable at low pH and more thermostable at 50 degrees C than peak two, while both peaks had an apparent KM of 52 mumol/l. Apart from the different proportions of the peaks separated by gel filtration, the results for the three tissues were similar. The properties of alpha-L-fucosidase studied were similar for control and cystic fibrosis liver or skin fibroblasts.