[Spectra of circular dichroism of proteinase inhibitors from corn].

The circular dichroism spectra of trypsin and chymotrypsin inhibitors from corn seeds were investigated. The spatial organization of the inhibitor molecules was shown to be different. The effects of guanidine chloride and temperature on these proteins suggest that the trypsin inhibitor from corn is much more stable towards the denaturating influences than the chymotrypsin inhibitor.

[Conformational changes during proteinase inhibitor proteins interaction with chymotrypsin].

Using CD-spectroscopy and fluorescent probe technique, the formation of complexes of chymotrypsin with two highly efficient protein inhibitors of plant origin, e. g. inhibitors from pea seeds and potato tubers, was studied.

[Modification of tyrosine residues in the protein inhibitor of potato proteinases].

Treatment of a native protein inhibitor of proteinases by tetranitromethane results inmodification of 3 (out of 8) tyrosine residues in each of the two subunits within the inhibitor molecule. Nitration of surface tyrosines does not change the corformation of the protein and has no effect on its ability to inhibit chymotrypsin. At the same time the tetranitromethane-treated inhibitor possesses a decreased activity with respect to trypsin.

[Circular dichroism spectra of protein proteinase inhibitors].

The circular dichroism spectra of two protein proteinase inhibitors were studied. The CD spectrum of the kidney bean inhibitor is similar to those of other low molecular weight inhibitors from legume seeds. The potato inhibitor in its native state is characterized by a low content of alpha-helices, which is increased in the presence of sodium dodecyl sulfate.

[Interaction of protein inhibitor from potato (protein with pI 7.3) with proteinases].

The interaction between protein inhibitor of serine proteinases from potato (protein with pI 7.3) and enzymes was investigated. The main complex present in mixtures of the inhibitor with trypsin, chymotrypsin or subtilisin contained one dimeric inhibitor molecule and one molecule of either enzyme.