The Effect of Extraction Procedures on Catalase Activity of AM Freeze - thawed extract Homogenate

A B S T R A C T Evidence for the presence of peroxidative metabolism in rabbit alveolar macrophages (AM) has been obtained from the following observations: (a) catalase is present in high concentrations; (b) peroxidase activity could not be detected employing guaiacol as substrate; (c) the irreversible inhibition of AM catalase by aminotriazole served as a detection system for H202 and demonstrated increased intracellular H202 after phagocytosis; (d) formate oxidation, a marker of catalase-dependent peroxidations, occurs in resting AM and is increased by phagocytosis; (e) measurements of H202 accumulation in a dialysate of AM demonstrated twofold increase during phagocytosis; and (f) aminotriazole diminishes 02 utilization and '4CO2 production from labelled glucose and pyruvate. It is concluded that, while catalase-dependent H202 metabolism is not essential for particle entry, this pathway represents one of the metabolic pathways stimulated by particle entry in the AM.