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The bone marrow myelopeptide MP-2 (Leu-Val-Val-Tyr-Pro-Trp), exhibiting antitumor activity, and its retro-analogue (Trp-Pro-Tyr-Val-Val-Leu) were synthesized, and their properties were studied. The in vitro and in vivo activities of retro-MP-2 were comparable with those of MP-2. Both peptides equally restored the functional activity of T-lymphocytes inhibited by toxins released by HL-60 cells and inhibited by 70-82% the growth of various types of transplantable solid tumors: Ca-755 adenocarcinoma of the mammary gland, Lewis adenocarcinoma of the lung, and S180 sarcoma. The positions and intensities of the Cotton effects in CD spectra of the MP-2 peptide and its retro-analogue in various solvents are almost indistinguishable. The positions of extrema and integral intensities of the amide I and amide A bands in IR spectra of both peptides were practically identical. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 3; see also http://www.maik.ru.

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Peptide Leu-Val-Cys-Tyr-Pro-Gln, identical to the bone marrow peptide MP-3, and its Val3 and Ser3 analogs, lacking SH-group, were synthesized by conventional methods of peptide chemistry in solution and, along with the MP-3 S-S-dimerization product, were studied with respect to their effect on the macrophage phagocytic activity. It was shown that the activity was only enhanced by peptide MP-3, which demonstrated the essential role of the SH-group in this function. The dimer analog of MP-3, unlike dimer analogs of other monocysteine-containing peptides, glutathione and HP5b, did not exhibit the inhibitory effect.

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