Inhibition of bovine heart adenosine deaminase activity by some pyrimidine analogues

Some pyrimidine analogues--especially 6-azauridine and 5-azacytidine at a final concentration of 1 mmol dm-3--significantly depressed adenosine deaminase activity isolated and purified from bovine heart. Both the above mentioned azapyrimidine nucleosides were effective competitive inhibitors of this enzyme. The inhibitory effect of some clinically used pyrimidine analogues may be of importance for explanation of their mechanisms of action on the cell metabolism.