title: Partition of trypsin and Kazal inhibitor in reaction mixtures with human serum.
abstract: The partition of trypsin and pancreatic secretory trypsin inhibitor (PSTI) in reaction mixtures with human serum was studied by electroimmunoassay and also by gel filtration on Sephadex G-200. The same pattern of trypsin complexes with alpha2-macroglobulin and alpha1-antitrypsin was observed in the presence or absence of PSTI. When sufficient trypsin was added to saturate the alpha2-macroglobulin, more complex with alpha1-antitrypsin was formed. A small amount of PSTI-trypsin complex was formed only when large amounts of trypsin and PSTI were present. The majority of PSTI was found in the fractions containing alpha2-macroglobulin, indicating the formation of a PSTI-trypsin-alpha2-macroglobulin complex. The remaining PSTI was eluted as free inhibitor. Increasing the added PSTI increased the fraction eluted as free inhibitor. alpha1-Antitrypsin and alpha2-macroglobulin appear to be much stronger than PSTI in their competition for trypsin in reaction mixtures of human serum, trypsin and PSTI.
mesh_terms: D006801:Humans; D007118:Immunoassay; D007700:Kinetics; D014359:Trypsin Inhibitor, Kazal Pancreatic / Q000097:blood*; D014361:Trypsin Inhibitors / Q000097:blood*
chemical_list: D014361:Trypsin Inhibitors; D014359:Trypsin Inhibitor, Kazal Pancreatic