Abstract
The activity of amine oxidase (flavine-containing) was measured in various organs. No activity could be detected in homogenates of the carotid body of the cat. Mixing experiments with this homogenate and rat liver mitochondria showed the presence of an inhibitor of amine oxidase activity in the carotid body. This inhibitor is inactivated by boiling. No inhibitor activity was found in the ganglion superior cervicale of the cat.