[Isolation and structure of peptides from oat (Avena sativa) seedlings].

The level of proteolytic activity in tissues of oat seedlings was characterized under acidic conditions, and the number and content of the main components in low-molecular-mass fractions of the extract were determined. The structures of the majority of predominant peptide components isolated from the extract were studied. The use of a database of protein structures helped suggest possible structures of protein precursors of the peptides isolated. Detailed information on a plant peptidome was obtained for the first time.

[The optical biosensor study of the redox partners interactions within the cytochrome P450 2B4-containing monooxygenase system in hydroxylation conditions].

Interactions between cytochrome P450 2B4, NADPH:cytochrome P450 reductase and cytochrome b5 have been investigated in the presence of a substrate (7-pentoxyresorufin) and an electron donor, NADPH, in the monomeric reconstituted P450 2B4-contained monooxygenase system. Each partner was immobilized via its amino groups on the carboxymethyldextran biochip surface of an optical biosensor IAsys+. It was shown that, despite immobilization of any of the partners (via their respective amino groups) onto the carboxymethyldextran surface of the IAsys+ optical biosensor, its activity didn't loss. The formation of binary d-Fp/d-2B4 complexes was registered. The association/dissociation rate constants (kon/koff) were (0,013 +/- 0,005) x 10(6) M(-1) x s(-1)/0,05 +/- 0,02 s(-1), equilibrium dissociation constant (K(D)) was (0,26 +/- 0,13) x 10(-6) M. Comparison of kon, koff and K(D) for d-Fp/d-2B4 complexes in oxidation conditions with corresponding constants for the oxidized protein forms--(0,10 +/- 0,03) x 10(6) M(-1) x s(-1)/(0,14 +/- 0,06) s(-1), (0,71 +/- 0,37) x 10(-6) M--shows that the decrease in kon and K(D) occurs due to the increase in lifetime during transition from oxidized to hydroxylation conditions. Complex formation between d-Fp and d-b5 was not registered in oxidation and hydroxylation conditions. The ternary d-Fp/d-2B4/d-b5 complexes formation was shown in hydroxylation and oxidation conditions.