1.Splenopentin--influence on antibody formation in immunosuppressed animals and on phagocytic capability of human granulocytes.
Diezel W1, Eckert R, Müller GM, Forner K, Sönnichsen N. Arch Geschwulstforsch. 1989;59(3):161-4.
Sublethally x-ray irradiated C57 Bl/6 Bln. mice (whole body irradiation with 600 cGy) were treated with or without a splenopentin derivative (DA SP-5: N alpha-acetyl-L-arginyl)-(N alpha-acetyl-L-lysyl)-L-glutamyl-L-valyl-L-tyrosine and compared for their capacity to produce antibodies against target sheep red blood cells. As demonstrated DA SP-5 treated mice produced antibodies earlier and in a higher level than animals untreated. Furthermore, DA SP-5 influences the phagocytic capability of human granulocytes in a dose dependent matter.
2.Immuno-regulating peptides, I. Synthesis and structure-activity relationships of thymopentin analogs.
Kisfaludy L, Nyéki O, Schön I, Dénes L, Ember J, Szporny L, Hajós G, Szende B. Hoppe Seylers Z Physiol Chem. 1983 Aug;364(8):933-40.
Seventeen peptides, related to thymopoietin pentapeptide, L-arginyl-L-lysyl-L-aspartyl-L-valyl-L-tyrosine (thymopentin) were synthesized by the stepwise strategy in solution. Of these, L-arginyl-L-lysyl-L-aspartic acid and L-arginyl-L-lysyl-L-aspartyl-L-valine, shortened from the C-terminus of the pentapeptide, exhibit significant immuno-stimulating potencies, exceeding those of thymopentin, both in vitro and in vivo immunological tests. Studies on the structure-activity relationships suggest that the potencial active site of thymopoietins is very sensitive to the N- and C-terminal elongations of the peptide chain. For thymic hormones, an active site carrying cumulative chemical signals is proposed instead of well-defined active centers.
3.The peptide NCbz-Val-Tyr-OMe and aromatic π-π interactions.
Nicholas S1. Acta Crystallogr C Struct Chem. 2015 Mar;71(Pt 3):211-5. doi: 10.1107/S2053229615002739. Epub 2015 Feb 18.
The peptide N-benzyloxycarbonyl-L-valyl-L-tyrosine methyl ester or NCbz-Val-Tyr-OMe (where NCbz is N-benzyloxycarbonyl and OMe indicates the methyl ester), C(23)H(28)N(2)O(6), has an extended backbone conformation. The aromatic rings of the Tyr residue and the NCbz group are involved in various attractive intra- and intermolecular aromatic π-π interactions which stabilize the conformation and packing in the crystal structure, in addition to N-H...O and O-H...O hydrogen bonds. The aromatic π-π interactions include parallel-displaced, perpendicular T-shaped, perpendicular L-shaped and inclined orientations.