Inhibition of dopamine beta-hydroxylase by 2-mercapto-1-methylimidazole

The inhibition of bovine dopamine beta-hydroxylase (dopamine beta-monooxygenase, EC 1.14.17.1) by 2-mercapto-1-methylimidazole has been studied using a simple, 'metal-free' assay system. 2-Mercapto-1-methylimidazole is an uncompetitive inhibitor of dopamine beta-hydroxylase with respect to ascorbate and a mixed type of inhibitor with respect to tyramine. These findings are consistent with 2-mercapto-1-methylimidazole interacting exclusively with the reduced form of dopamine beta-hydroxylase.