title: Acid-base properties of thymopoietin-type tri- and tetrapeptides and their derivatives.
abstract: The submolecular basicities of 21 immuno-modulating, thymopoietin-type di-, tri-, and tetrapeptides were studied and characterized in terms of group constants and partial microconstants. All compounds were derivatives of the H-Arg-Lys-Asp-OH tripeptide. Modifications within four covalent bonds of the basic site (esterification, acylation, curtailment or addition at C-terminal end, exchange of amino acids) cause significant changes in the scheme of protonation and in the individual basicity of proton binding sites. Configurational changes of the component amino acids, however, do not cause significantly different basicities in the diastereomers.
authors.affiliation: Department of Inorganic and Analytical Chemistry, L. Eötvös University, Budapest, Hungary.
authors.forename: B
authors.initials: B
authors.lastname: Noszál
authors.forename: R
authors.initials: R
authors.lastname: Kassai-Tánczos
authors.forename: J
authors.initials: J
authors.lastname: Nyíri
authors.forename: O
authors.initials: O
authors.lastname: Nyéki
authors.forename: I
authors.initials: I
authors.lastname: Schõn
mesh_terms: D000136:Acid-Base Equilibrium; D000595:Amino Acid Sequence; D001665:Binding Sites; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D013946:Thymopoietins
chemical_list: D009842:Oligopeptides; D013946:Thymopoietins