1985 Volume 16 Issue 2 Pages 220-222
Partially purified plasminogen activator (gPA) extracted from hypersensitivitytype murine lepromas in C57BL/6N mice after Sephacryl S-200 and DEAE Sepharose columns showed a unique substrate specificity for chromogenic substrates, distinct from that of urokinase-type PA (uPA), and tissue-type PA (tPA). It was revealed that gPA was with the highest substrate specificity for Ile-Pro-Arg-pNA (s-2288) (Km=1.4×10-4), second highest for Val-Leu-Lys-pNA (s-2251) (Km=5.2×10-4), and a fairly high affinity for Glu-Gly-Arg-pNA (s-2444) (Km=9.3×10-4), whereas it was found compatible with the substrate specificity of macrophage PA (mPA) secreted by thioglycollate stimulated mouse peritoneal macrophages in culture. An electrophoretic enzymography demonstrated that gPA consists of two molecular forms (subspecies) with Mr=45, 000 and 24, 000, distinct from uPA (Mr=55, 000 and 33, 000) and tPA (Mr=72, 000), whereas identical with the enzymographic pattern of mPA (Mr=45, 000 and 24, 000). An immunoblotting technique further revealed that gPA is antigenically not related to uPA and tPA.
A PA with a characteristics identical to macrophage PA was found in inflammatory tissue during the development of hypersensitivity-type of murine lepromas, suggesting its possible immuno-modulatory role in the inflammation.
