[Synthesis and catalytic activity of polypeptides of regular structure containing polyfunctional amino acids]

Synthesis and study of catalytic properties of a series of regular polypeptide which contain residues of polyfunctional amino acids forming the active centre of esterases are described viz. (Ala-Tyr-Glu)n, (His-Ser-Glu)n, (Glu-His-Glu)n, (His-Glu)n, (Ser-His-Glu)n, His-(Tyr-Glu)n. Possibility of constructing catalytically active model polypeptides which can substitute some hydrolytic enzymes is assessed. Monomers for polycondensation were been synthesized by carbodiimide method in solution, and polypeptides were obtained via 2,4,5-trichlorphenylates. Gel-filtration was used for fractionation of and molecular mass-determination of polypeptides. Catalytic properties of the synthetic polypeptides were studied in hydrolysis of p-NFA, Z-L-Ala-ONp, and Z-D-Ala-ONp. It was revealed that polypeptides (Ala-Tyr-Glu)n and (His-Ser-Glu)n possess, in hydrolysis of Z-L-Ala-ONp- and Z-D-Ala-ONp some enantioselectivity with the value of KD/KL 1.3 and 1.17, resp. The upper and lower limits of enantioselectivity as dependent of the molecular mass of the corresponding polypeptides have been determined.