Chloride binding to alkaline phosphatase. 113Cd and 35Cl NMR.
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چکیده
منابع مشابه
Phosphate Binding to Alkaline Phosphatase
The metal ion dependence of a2P binding to Escherichia coli alkaline phosphatase has been studied by means of equilibrium dialysis. Whereas the apoenzyme does not bind phosphate (no sites with K < 5 X 10-5 M), the addition of 2 Zn(I1) cations per molecule induces the tight binding of 1 phosphate dianion (K = 6 X 1OF M). The magnitude of this binding constant is affected by ionic strength, pH, a...
متن کاملAllosteric interactions between metal ion and phosphate at the active sites of alkaline phosphatase as determined by 31P NMR and 113Cd NMR.
““Cd and :“P NMR have been used to determine the effect of variations in the nature and stoichiometry of bound metal ion and pH on the allosteric interactions (negative cooperativity) induced on association of phosphate with the dimeric zinc metalloenzyme Escherichia coli alkaline phosphatase. At pH 8.0, successive additions of an extra two Zn’+ ions and one Mg”+ ion to the Znzs+ enzyme result ...
متن کامل31P NMR of alkaline phosphatase. Dependence of phosphate binding stoichiometry on metal ion content.
Alkaline phosphatase of Escherichia coli (a dimeric zinc metalloenzyme of identical subunits) containing either 2 catalytic Zn(II) ions or 2 catalytic Cd(I1) ions shows absolute negative cooperativity of phosphate binding as determined by 31P NMR of enzyme-bound phosphate species. With excess phosphate at millimolar concentrations, only 1 mol of noncovalent phosphate complex, E.P (31P resonance...
متن کاملFunctional Significance of Calcium Binding to Tissue-Nonspecific Alkaline Phosphatase
The conserved active site of alkaline phosphatases (AP) contains catalytically important Zn2+ (M1 and M2) and Mg2+-sites (M3) and a fourth peripheral Ca2+ site (M4) of unknown significance. We have studied Ca2+ binding to M1-4 of tissue-nonspecific AP (TNAP), an enzyme crucial for skeletal mineralization, using recombinant TNAP and a series of M4 mutants. Ca2+ could substitute for Mg2+ at M3, w...
متن کاملAlkaline phosphatase. 31P NMR probes of the mechanism.
31P NMR signals from substrates and products of alkaline phosphatase have been adapted to measure the rates and product ratios for the hydrolysis and phosphotransferase reactions from pH 6 to 10. Below pH 8, glycerol is a poorer acceptor than H2O (glycerol phosphates:Pi = 0.5). Tris is a more effective acceptor below pH 8, showing a maximum acceptor efficiency at pH 8 (Tris phosphate:Pi = 2). P...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1984
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)90618-6