Study on the inhibition of adenosine deaminase

4(R)-(1-Hydroxyethyl)-5-methyl-1-beta-D-ribofuranosylimidazole (10), which contains only the asymmetric alcohol center of the diazepinol ring of the adenosine deaminase inhibitor coformycin (12), is a much less potent inhibitor of the enzyme but still binds to the enzyme about as tightly as the normal substrate.