Allosteric modification of adenylate deaminase activity initiation of adenosine deaminase activity by potassium ions

Autor: Pekkel', V. A., Kirkel', A. Z.
Zdroj: Bulletin of Experimental Biology and Medicine; November 1978, Vol. 86 Issue: 5 p1442-1444, 3p
Abstrakt: Activation of purified adenylate deaminase from the duck myocardium by K+ ions is accompanied by a change in the substrate specificity of the enzyme and appearance of ability to deaminate adenosine and adenine. Adenosine deaminase activity appears with K+ in a concentration exhibiting maximal stimulating effect (0.15 M) and it increases with an increase in the K+ concentration, parallel with a decrease in Hill's coefficient. It can be concluded from the pH dependence, the character of inhibition by phosphate, and the effect of cations of the alkali metals that deamination of adenosine takes place at natural combining sites of adenylate deaminase, the conformation of which is modified by the activator.
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