title: Interaction between Serratia protease and human plasma alpha 2 macroglobulin.
abstract: Serratia protease (TSP) [EC 3.4.24] was bound stoichiometrically to alpha 2 macroglobulin (alpha 2M), which was purified and crystallized from human plasma, but apo TSP was not bound. On formation of the TSP-alpha 2M complex the enzymatic activity of the bound TSP was affected with respect to substrates; Km values of the bound TSP were unchanged but Vmax values were reduced. alpha 2M was cleft at the mid-region of its subunits chains by TSP, which resulted in a conformational change of the alpha 2M molecule with TSP.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008666:Metalloendopeptidases; D011487:Protein Conformation; D012705:Serratia / Q000201:enzymology*; D013056:Spectrophotometry, Ultraviolet; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: D000511:alpha-Macroglobulins; D010450:Endopeptidases; D008666:Metalloendopeptidases