[Role of charge and hydrophobic effects in reactions of peptide substrates and inhibitors with thrombin].

A substrate and inhibitor analysis of the thrombin interaction with synthetic peptide substrates and inhibitors of differing hydrophobicity and volume of the side amino acid residue, localized in the sub-centers thrombin S2 and S3 were carried out. The kinetic parameters of individual stages of the enzymatic reaction process (K(S), k2, k3) were estimated. It is shown that the efficiency of acylation and deacylation stages of the enzymatic reaction decreases with increasing hydrophobicity of the substituent in P2 as well as P3, at the same time the affinity of selected peptides toward enzyme is steadily increasing.

[Thrombin inhibitors which display antibacterial activity].

The investigation of cytotoxicity and antibacterial activity of the novel thrombin inhibitors containing retro-D-sequences -D-Arg-D-Phe--modified by D-arginine amino group by the residues of lauric acid or chromone-contained substituent, in comparison with known cationic preservative Nalpha-lauroyl-L-arginine ethyl ester (LAE) have been carried out. It has been shown that compound Laur-D-Arg-D-Phe-OMe has a similar cytotoxicity with LAE, and Chrom-D-Arg-D-Phe-OMe has almost twice higher toxicity than it fatty moiety contained analogues. Antibacterial activity of Laur-D-Arg-D-Phe-OMe against Staphylococcus aureus and Bacillus subtilis is close in action to LAE.

[Antithrombic activity of N(alpha)-lauroyl-L-arginine ethyl ester (LAE) and 9-fluorenylmethoxycarbonyl-L-arginine methyl ester (Fmoc-L-Arg-OMe)].

Simple synthetic compounds of lauroyl-arginine ethyl ester (LAE) and 9-fluorenylmethoxycarbonyl-L-agrinine methyl ester (Fmoc-Arg-OMe) were studied for their inhibitory effect on the hydrolysis of chromogenic substrate Tos-Gly-Pro-Arg-pNA (Chromozym TH) by thrombin with K(i) for LAE 1.92 microM and 77 microM for Fmoc Arg-OMe. It was shown that LAE inhibits thrombin activity almost 20 times more strongly than trypsin (K(i) = 18.

[The synthesis of arginine derivatives of chromone and azauracil].

The coupling of N-succinimide esters of 3-[7-hydroxy-3-(4-methyl-1,3-thiazol-2-yl)-6-ethyl-4-oxo-4H-chromen-2-yl]propanoic acid and 5-carboxymethyl-6-azauracil with free arginine yielded the corresponding arginine derivatives, which were purified by crystallization. The structures of the compounds were confirmed by 1H NMR spectroscopy. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2006, vol.

[Kinetics of trypsin-catalyzed hydrolysis of some arginine-containing peptide methyl esters].

The kinetics of trypsin-catalyzed hydrolysis (at pH 8.5) of methyl esters of some synthetic dipeptides containing the residues of both arginine and L(D)-p-fluorophenylalanine or L(D)-tyrosine has been studied. The digestion of Tos-(pF)Phe-Arg-OMe was shown as unfollowing the Michaelis-Menten kinetic since in the reaction course the substrate activation is observed and while the reaction product is the enzymatic process inhibitor.