Abstract
Dopa decarboxylase was isolated from rat liver and the effects of active polypeptides and prostaglandins on dopa decarboxylase activity were investigated. Polypeptides and prostaglandins used were as follow: secretin, pancreozymin, glucagon, insulin, eledoisin, kallikrein, bradykinin, angiotensin II, gastrin, prostaglandin E1, E2 and F2α. Only kallikrein among these compounds inhibited the dopa decarboxylase activity at doses from 0.3 to 1.0 unit per 3 ml. According to the Lineweaver-Burk plot, this inhibition appeared to be non-competitive. It is suggested that kallikrein may exert some influence on the conversion of dopa to dopamine.
