Studies on the catalytic residues at the active site of human liver alpha-L-fucosidase.
Publication/Presentation Date
7-1-1985
Abstract
Kinetic studies and chemical modifications were performed on purified human liver alpha-L-fucosidase (alpha-L-fucoside fucohydrolase, EC 3.2.1.51) in an attempt to identify the catalytic residues at the active site. Plots of log Vmax vs. pH (computer-fitted to a theoretical model) displayed two apparent pK values, of approx. 3.8 and 7.3. The temperature dependence of these pK values yielded heats of ionization of 3 and 0 kcal/mol from Van't Hoff plots for the lower and higher pK values, respectively. Reaction of alpha-L-fucosidase with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and sodium p-(hydroxymercuri)benzoate resulted in complete inactivation of the enzyme. Other nonspecific inactivators had little or no effect on enzyme activity. These results suggest two carboxyl groups whose ionization state is important to activity, a non-active-site cysteine residue important to activity, and at least one active-site carboxyl group.
Volume
829
Issue
3
First Page
303
Last Page
310
ISSN
0006-3002
Published In/Presented At
White, W. J., Jr, Schray, K. J., & Alhadeff, J. A. (1985). Studies on the catalytic residues at the active site of human liver alpha-L-fucosidase. Biochimica et biophysica acta, 829(3), 303–310. https://doi.org/10.1016/0167-4838(85)90237-7
Disciplines
Medicine and Health Sciences
PubMedID
4005264
Department(s)
Department of Medicine
Document Type
Article