Two Groups of Protease Inhibitors Functionally Active in Buckwheat Seeds

Protein inhibitors of proteolytic enzymes frequently occur in different tissues of animals, plants and microorganisms. They regulate the activity of endogenous proteases thus controlling a rich variety of intracellular metabolic events. In plant tissues, such as seeds, tubers and leaves, a number of inhibitors are, however, found which affect enzymes produced by outside objects rather than their own proteases. Circumstantial evidence suggested that these inhibitors can be involved in plant protection against the destructive action of phytopathogenic proteases / Ryan, 1973; Ryan, 1974 I. In this work we identified and described a group of protease inhibitors from buckwheat seeds. An effort was also made to find out what function these inhibitors perform in the seeds. Materials and Methods Dry buckwheat seeds Fagopyrum esculentum Moench. (Shatilovskaja 5) were used in the work. To determine the activity of the trypsin inhibitors (TI), inhibitor-containing solutions (1-10,.d) were mixed with 5,.d of trypsin solution (I mg / ml) and the mixture incubated for 10 min at room temperature. After incubation the remaining activity of trypsin was assayed according the method of Erlanger et al. /1961 / with 0.2 mM solution of N-benzoyl-D, L-arginine p-nitroanilide as substrate in 0.5 M K,Na-phosphate, pH 7.5. The amount of inhibitor decreasin