Cystic fibrosis serum α- l-fucosidase: Confirmation of normal activity levels and normal kinetic and isoelectric focusing properties

Abstract

Comparable α- l-fucosidase activity was found for normal and cystic fibrosis sera, 7.8 ± 3.3 and 9.8 ± 4.7 nmol/min/ml, respectively. Isoelectric focusing of normal and cystic fibrosis sera α- l-fucosidase revealed similar isoelectric profiles with most activity between isoelectric points of 4.7–5.4. Kinetic analysis of normal and cystic fibrosis sera α- l-fucosidase revealed identical apparent Michaelis constants for the 4-methylumbelliferyl substrate (51 ± 6 μmol/l and 50 ± 8 μmol/1, respectively), similar pH optima curves (both have broad optima between pH 4.8 and 6.5) and identical thermostability curves at three different preincubation temperatures (37°, 45° and 55°C).