[New donor-acceptor pairs for fluorogenic substrates with intramolecular fluorescence energy transfer for thrombin and trypsin]. / Novye donorno-aktseptornye pary dlia fluorogennykh substratov s vnutrimolekuliarnym perenosom énergii fluorestsetsii dlia trombina i tripsina.

New substrates for thrombin and trypsin are described: a fluorogenic substrate Abz-Pro-Arg-Gly-Nph (I), whose action is based on intramolecular fluorescence energy transfer, and H-D-Trp-Pro-Arg-pNA (II), which can be used both as a chromogenic substrate and as a substrate with the intramolecular fluorescence energy transfer. In substrate (I), a 4-nitrophenylhydrazide group was first used as an acceptor of excitation energy of the 2-aminobenzoyl group. The substrate is poorly hydrolyzed by thrombin (kcat/K(m) = 1.4 x 10(3) M-1 s-1) and is efficiently cleaved by trypsin (kcat/K(m) = 3.15 x 10(6) M-1 s-1). The hydrolysis of (II) can be monitored both spectrophotometrically, by absorbance at 405 nm, and from the increase in fluorescence at 340 nm. In the efficiency of hydrolysis with thrombin (kcat/K(m) = 3.0 x 10(6) M-1 s-1), compound (II) is comparable with the known chromogenic substrates for this enzyme. The proposed donor-acceptor pairs are promising in designing substrates with the intramolecular fluorescence energy transfer for a variety of proteolytic enzymes.

Synthesis and study on a novel inhibitor of thrombin containing no side chain at the P1 position of the polypeptide chain.

The presented work allows one to speculate that the hydrophobic contacts of the residues located at the P2 and P3 positions with the corresponding subsites of thrombin (S2 and S3) allow the synthesis of compounds that can react with thrombin specifically and probably may not interact with other trypsin-like serine proteases. Substitution of proline by m-Abz-residue may result in the development of novel substrates and inhibitors for thrombin.