title: The synthesis and some biological properties of N-(6-purinyl)peptides.
abstract: The chemical synthesis and biological properties of N-(6-purinyl)peptides are described. N-(6-Purinyl)amino-acid derivatives were synthesized and condensed with amino acid esters and peptide esters using the dicyclohexylcarbodiimide/N-hydroxysuccinimide method. The products were isolated via gel filtration on Sephadex G-10 in 0.05M NH4HCO3 followed by either ion exchange chromatography on SP-Sephadex or by preparative HPLC. The methyl esters were saponified and the tert-butyl ester group was removed by treatment with trifluoroacetic acid without damaging the purinyl residue. N-(6-Purinyl)peptides were characterised by chromatographic and spectroscopic methods. Acid hydrolysis of N-(6-purinyl)-L-amino acids caused the racemization of the neighbouring L-amino acid. Model studies were performed with N-(6-purinyl)-L-alanine, N-(6-purinyl)-D-alanine, N-(6-purinyl)-L-alanyl-L-leucine and N-(6-purinyl)-D-alanyl-L-leucine. After acid hydrolysis the N-(6-purinyl)amino acids were totally racemized and the N-(6-purinyl)dipeptides formed 14% of the enantiomer of alanine. The N-(6-purinyl)-omega-amino acids and the N-(6-purinyl)peptides were screened in a limited number of tests as immunomodulators (antibody-secretion, phagocytosis, cytostatic activity of macrophages) and as cytotoxic agents.
mesh_terms: D000276:Adjuvants, Immunologic / Q000138:chemical synthesis; D000818:Animals; D000890:Anti-Infective Agents / Q000138:chemical synthesis; D000917:Antibody Formation / Q000187:drug effects; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D010455:Peptides / Q000138:chemical synthesis* / Q000494:pharmacology; D011687:Purines / Q000138:chemical synthesis* / Q000494:pharmacology; D011817:Rabbits; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D000276:Adjuvants, Immunologic; D000890:Anti-Infective Agents; D010455:Peptides; D011687:Purines