Affordable Access

Resistance to inactivation by EGTA of the enzyme-substrate and enzyme-phosphate complexes of alkaline phosphatase.

Authors
  • Pike, S J
  • Duggleby, R G
Type
Published Article
Journal
The Biochemical journal
Publication Date
Jun 15, 1987
Volume
244
Issue
3
Pages
781–785
Identifiers
PMID: 3128267
Source
Medline
License
Unknown

Abstract

Bovine intestinal mucosal alkaline phosphatase is inactivated by the chelating agent EGTA. Several concentrations of the enzyme were incubated with EGTA and a range of concentrations of the substrate p-nitrophenyl phosphate to determine the substrate concentration as a function of time. As predicted by a recently developed theory [Duggleby (1986) J. Theor. Biol. 123, 67-80], catalysis ceases before all substrate is exhausted. An analysis of these final substrate concentrations according to the theory revealed that, whereas the free enzyme is unstable, the effect of EGTA is counteracted when either the substrate or product (phosphate) is bound. Comparison of the results with those obtained by direct stability measurements and steady-state kinetic experiments gave a qualitatively and quantitatively consistent body of evidence in support of this interpretation.

Report this publication

Statistics

Seen <100 times