CHARACTERIZATION OF AMINE OXIDASE ACTIVITIES IN MACROPHAGES FROM HUMAN PERIPHERAL-BLOOD

A sensitive assay for the determination of hydrogen peroxide formation and a method for the identification and characterization of amine oxi dases in cells and other oxidase sources of limited accessibility are described. The enzymes are characterized by substrate and inhibitor pa tterns. The method was applied to the identification and characterizat ion of polyamine oxidizing enzymes in macrophages from human periphera l blood. The major oxidase activity in these cells was found to be a t issue-type polyamine oxidase, but with distinct characteristics. Diami ne oxidase and monoamine oxidase activities were also detected in homo genates of macrophages. Since the formation of toxic products by a rel easable polyamine oxidase is supposed to be an integral part of a regu latory function of macrophages, we consider our work as a basis for th e elucidation of this function.