title: Internalization of serratial protease into cells as an enzyme-inhibitor complex with alpha 2-macroglobulin and regeneration of protease activity and cytotoxicity.
abstract: Extracellular serratial protease (56,000 Da) is known to be cytotoxic. Fluorescein isothiocyanate-labeled protease was found to form a complex with human alpha 2-macroglobulin (alpha 2M), and this enzyme-inhibitor complex was purified. The protease was found to be internalized by fibroblasts in culture as a complex with alpha 2M, which resulted in cell destruction. Regeneration of enzyme activity was confirmed in cells after 2-3 h of incubation. Chicken egg-white ovomacroglobulin, a homolog of human alpha 2M, formed a complex with this enzyme similarly and more tightly but failed to exhibit protease activity, cytotoxicity, and internalization into cells.
mesh_terms: D001667:Binding, Competitive; D002460:Cell Line; D002470:Cell Survival; D004705:Endocytosis; D005347:Fibroblasts / Q000378:metabolism*; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008856:Microscopy, Fluorescence; D010447:Peptide Hydrolases / Q000378:metabolism*; D011480:Protease Inhibitors / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism; D012706:Serratia marcescens / Q000201:enzymology*; D013861:Thiocyanates; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011480:Protease Inhibitors; D011971:Receptors, Immunologic; D013861:Thiocyanates; D000511:alpha-Macroglobulins; D010447:Peptide Hydrolases; D016650:Fluorescein-5-isothiocyanate