HUMAN ERYTHROCYTE MULTICATALYTIC PROTEINASE - ACTIVATION AND BINDING TO SULFATED GALACTOSYLCERAMIDES AND LACTOSYLCERAMIDES

Chymotrypsin-like activity of multicatalytic proteinase (MCP) purified from human erythrocytes was selectively activated 2.5 - 3.5-fold by sulfated glycolipids such as galactosylceramide sulfate (SM4) and lactosylceramide sulfate (SM3) but not by other glycolipids including galactosylceramide (GalCer), lactosylceramide (LacCer), GDla, GMl and GM3. Heparin also selectively activated trypsin-like activity 2.5-fold, while other mucopolysaccharides did not. This proteinase molecule bound specifically and with high affinity to both SM4 and SM3, but not to GalCer, LacCer and GM3. The binding of SM4 and SM3 to the enzyme molecule was also confirmed by thin layer chromatography. © 1991.