Inhibition of smooth muscle 5′-nucleotidase by imidazole and its reversal by magnesium

Imidazole, commonly used as an effective pH-buffering reagent in aqueous media maintained at pH 7-8, was found to depress the 5'-nucleotidase (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) activity of microsomal membrane fraction isolated from rat vas deferens smooth muscle in a dose-dependent manner in the absence of added Mg2+. Such an inhibitory effect of imidazole on the smooth muscle 5'-nucleotidase was not dependent upon the purity or …