Immunological Properties and Immunoelectron- Microscopic Localization of Angiotensin Converting Enzyme in Sarcoid Lymph Nodes

Abstract

Angiotensin converting enzyme (ACE) that was partially purified from sarcoid lymph nodes was identical with that from human kidney, lung and plasma with respect to apparent molecular weight, Km value, heat sensitivity and inhibition by captopril.
Antigenic determinants of ACE of sarcoid lymph node were indistinguishable from those of kidney, lung and plasma by two different immunologic methods, i.e. titration of ACE activity and double immunodiffusion using the antibody against human kidney ACE.
Immunofluorescent and immunoelectron-microscopic studies showed that ACE was localized on the surface of plasma membrane and microvilli of epithelioid cells in the sarcoid granuloma of lymph node.