[Inhibition of exogenous serine proteinases by a trypsin inhibitor from the buckwheat IT-1 seeds].

The possibility of inhibition of exogenous trypsin- and chymotrypsin-like proteinases by a proteinase inhibitor from buckwheat (IT-1) seeds has been studied. The inhibition constants for bovine trypsin and alpha-chymotrypsin and human granulocyte cathepsin G by IT-1 are equal to 1.1, 67 and 200 nm, respectively. The specificity of IT-1 with regard to its primary sequence adjacent to the active center and to its homology with inhibitors pertaining to the potato inhibitor I family has been carried out. It is concluded that by virtue of the basic nature of the P1 (Arg) residue in the active center IT-1 is not capable to bind human granulocyte elastase.