Synthesis and Antithrombin Activity of Phosphoalanine-Containing Peptides

Boc/Tos-L-Phe-L-Arg-Xaa tripeptides (where Xaa = L-Ala-OBu ^t , L-Ala, or DL-Ala ^P (OC₂H₅)₂) were synthesized by conventional methods of peptide synthesis in solution. Special features of their interaction with thrombin and trypsin were studied. Unlike trypsin, thrombin did not catalyze the hydrolysis of the L-Arg–L-Ala ^P (OC₂H₅)₂ bond. The Tos-L-Phe-L-Arg-DL-Ala ^P (OC₂H₅)₂ peptide was the most active inhibitor of thrombin among all the compounds studied. The relationship between the structure and inhibitory action of the synthesized peptides is discussed.²     

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