Inhibition of dopamine-beta-hydroxylase by carnosine

Dopamine-beta-hydroxylase was partially purified from bovine adrenal medulla and the effect of carnosine on the dopamine-beta-hydroxylase activity was investigated. Carnosine significantly inhibited the enzyme activity at the concentrations higher than 0.5 mM. According to the Lineweaver-Burk plots, the inhibition observed appeared to be a non-competitive type with the substrate, tyramine.