Kinetic characteristics of some inhibitors of matrix-induced alkaline phosphatase
Curti, C.; Pizauro, J.M.; Ciancaglini, P.; Leone, F.A.
Cellular and Molecular Biology 33(5): 625-635
1987
ISSN/ISBN: 0145-5680 PMID: 3690615 Document Number: 292794
The study of the action of some inhibitors on the kinetic properties of matrix-induced membrane-bound alkaline phosphatase revealed that vanadate (Ki = 8.5 .mu.M) and arsenate (Ki = 33.8 .mu.M) are efficient competitors whereas inorganic phosphate acts as a linear mixed inhibitor (Ki = 1.23 mM). Levamisole (Ki = 29.2 .mu.M), theophylline (Ki = 83.9 .mu.M) and L-phenylalanine (Ki = 4.52 mM) are uncompetitive inhibitors and ZnCl2 is a noncompetitive one (Ki = 13.9 .mu.M). For 1,10-phenanthroline up to 85% of the activity was recovered by exhaustive dialysis whereas for EDTA erratic recoveries were obtained. The inhibition of PNPP-A activity by DFP suggests that a serine residue is essential for phosphohydrolytic activity.