Some hydrazides of pyrrol-1-ylbenzoic and pyrrol-1-ylphenylacetic acids were prepared, and their effect on cop-per-dependent amine oxidases (Cu-AOs) and FAD monoamine oxidases (MAOs) activities was tested. The compounds were not substrates for Cu-A0 enzymes but acted as noncompetitive inhibitors. Hydrazides of pyrrol-1-ylphenylacetic acids were highly specific for plasma amine oxidase (Ki= 0.5-1 yM). In contrast, all the ...