Evidence on the involvement in inflammation of an enzyme resembling aminopeptidase B

The presence of arginine aminopeptidases in samples obtained from human oral abscesses and cysts (acute or chronic) and the respective serum was studied, with special reference to the possible involvement of aminopeptidase B (APB). All pus and inflammatory cyst fluid samples studied contained an enzyme closely related to rat liver APB (true APB). The serum of these patients revealed an APB-like enzyme when chromatographed on Sephadex G-100 Superfine columns, but the peak representing this enzyme disappeared when penicillin was administered to the patient. There was no APB like enzyme in the serum of persons with no oral abscesses. The results supported the earlier suggestions of APB as an aminopeptidase being extracellularly active in pathological conditions only. It is possible that an APB-assay in serum could show the efficacy of the treatment with antibiotics in the cases described. The APB-like enzyme studied differed from the rat liver enzyme as regards substrate specificity and molecular weight, but resembled it in several other properties.