Evidence of semicarbazide-sensitive amine oxidase activity in guinea pig tissues.

Lung, heart tissues and blood plasma of guinea pigs were investigated to see if tissue-bound semicarbazide-sensitive amine oxidase activities with a high affinity for benzylamine (Bz.SSAO) were present in this species as well as in others. This paper shows that these enzymic activities are present in guinea pig lung and heart where they are mainly localized in the cytosol and in microsomal fraction. These activities have a high affinity for benzylamine and appear unable to oxidize histamine at an appreciable rate in agreement with the observation that the purified Bz.SSAO of guinea pig skin shows weak histaminase activity. These guinea pig Bz.SSAO activities show some homology with the pure pig plasma benzylamine oxidase. They crossreact with the antibodies raised in the rabbit against the pig plasma enzyme. Benzylamine oxidase activity was also found in guinea pig blood plasma.