[Effect of diphosphonic acids on alkaline phosphatase activity].
Kinetics was studied for the alkaline phosphatase activity inhibition by diphosphonic acids. When the ratio of Mg2+ and substrate (S) concentrations [( Mg2+]/[S]) is equal to 10, the process constants for methylene diphosphonic, amino methylene diphosphonic and hydroxyethylidene diphosphonic acids are 0.14, 0.12 and 0.35 mM, respectively. The inhibition is of competitive character. An increase in the Mg2+ concentration to the [Mg2+]/[S] = 40 ratio lowers the inhibition degree for all three diphosphonates; it follows a mixed mechanism. Thus, the inhibition of the alkaline phosphatase activity by diphosphonic acids is due to both competition of the inhibitor for the enzyme active centre and a decrease in the Mg2+ concentration, the phosphatase activator, because of Mg2+ complexing with diphosphonates.
D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D003864:Depression, Chemical; D004164:Diphosphonates / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007700:Kinetics; D008274:Magnesium; D013379:Substrate Specificity
D004164:Diphosphonates; D000469:Alkaline Phosphatase; D008274:Magnesium
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