Stability and specificity of extracellular protein inhibitor for trypsin from Actinomyces janthinus 118
Andreeva, N.A.; Chermenskiĭ, D.N.
Biokhimiia 44(5): 838-843
1979
ISSN/ISBN: 0320-9725 PMID: 36928 Document Number: 147156
Some properties of protein inhibitor for trypsin (TI) from A. janthinus 118 were studied. TI has an antitrypsin activity within a wide pH range with a maximum at .apprx. 9.5. At 4.degree. and 20.degree. C, TI is stable for 24 h within the pH range of 6.0-11.0. At 100.degree. 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 h. TI inhibits trypsin, fibrinolysin, subtilisin, Pronase and terrilytin, but have no effect on chymotrypsin, thrombin, papain and pepsin. The kd for the trypsin-inhibitor complex were 1.7 .cntdot. 10-8 M, 4.1 .cntdot. 10-9 M and 2.4 .cntdot. 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 1 .cntdot.10-9 M and 4 .cntdot. 10-10 M with casein and carbobenzoxyl-L-alanyl-L-alanyl-L-leucin p-nitroanilide used as substrates, respectively.