Concanavalin-A-colloidal gold (Con-A-G) complex and adenylate cyclase activity were detected simultaneously in electron microscopic preparations of human fibroblast cultures, by a combined histochemical technique. The colloidal gold particles appeared as round bodies which could be readily differentiated from the amorphous product of the adenylate cyclase enzyme reaction. The combined technique makes possible the simultaneous visualization of the bound ligand (i.e. of its binding site), and of the enzyme activated by the lignad. Treatment of the cells with Con-A accounted for a considerable increase in intracellular adenylate cyclase activity. The activity increase was disproportionally greater than the amount of bound ligand, and it also appeared in localizations showing no indication of ligand binding. Treatment of the fibroblasts with Con-A was followed by internalization of the lignand and the enzyme inside at least seemingly segregated vesicles.
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)