Observations on the substrate specificity of aminne oxidases.

A number of compounds have been tested as substrates of, first, the amine oxidases of rabbit and guinea-pig liver and of goat, pig, horse, and dog plasma and, second, the "diamine oxidase" of pig kidney. Of the three xylylenediamines [di(aminomethyl)benzenes]tested, m-xylylenediamine was found to be a substrate of the liver oxidase. All the plasma oxidases tested acted on both m- and o-xylylenediamine. Both 3- and 4-picolylamine (3- and 4-aminomethylpyridine) were readily oxidized by the liver enzymes; all the plasma oxidases tested oxidized 2-, 3-, and 4-picolylamine. 4-Picolylamine was more rapidly oxidized by horse and dog plasma than any other substrate hitherto examined.