title: [Stability and specificity of extracellular protein inhibitor for trypsin from Actinomyces janthinus 118].
abstract: Some properties of protein inhibitor for trypsin (TI) from Act. janthinus 118 were studied. It was shown that TI has an antitrypsin activity within a wide pH range with a maximum at about 9,5. At 4 degrees and 20 degrees C TI is stable for 24 hours within the pH range of 6,0--11,0. At 100 degrees C TI is more stable in the slightly acid region of pH than at neutral or alkaline conditions. Trypsin and chymotrypsin inactivate the inhibitor for 8 hours. TI inhibits trypsin, fibrinolysin, subtilisin, pronase and terrilytin, but have no effect on chymotrypsin, thrombin, papain and pepsin. The dissociation constants for the trypsin-inhibitor complex were found to be 1,7.10-8 M, 4,1.10-9 M and 2,4.10-10 M, with casein, p-nitroanilide benzoylarginine and tosylarginine methyl ester used as substrates, respectively. The corresponding dissociation rate constants for the subtilisin-inhibitor complex were equal to 1.10-9 M and 4.10-10 M with casein and carbobenzoxy-L-alanyl-L-alanyl-L-leucin p-nitroanilide used as substrates, respectively.
mesh_terms: D000190:Actinomyces / Q000032:analysis*; D004355:Drug Stability; D010450:Endopeptidases / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013329:Structure-Activity Relationship; D014361:Trypsin Inhibitors / Q000494:pharmacology
chemical_list: D014361:Trypsin Inhibitors; D010450:Endopeptidases
vernacular_title: Stabil'nost' i spetsifichnost' vnekletochnogo belkovogo ingibitora tripsina iz Actinomyces janthinus 118