Interactions between copper (II) ions and L-threonine, L-allo-threonine and L-serine in aqueous solution
| Autor: | René-Paul Martin, Annie Rossi, Pierre Grenouillet, Marius Ptak |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
Threonine
Circular dichroism Optical Rotation Stereochemistry Molecular Conformation chemistry.chemical_element Ligands Biochemistry Genetics and Molecular Biology (miscellaneous) Serine Isomerism Side chain chemistry.chemical_classification Aqueous solution Binding Sites Ligand Circular Dichroism Hydrogen-Ion Concentration Deuterium Copper Amino acid chemistry Spectrophotometry Mathematics Protein Binding |
| Zdroj: | Biochimica et biophysica acta. 322(2) |
| ISSN: | 0006-3002 |
| Popis: | In order to understand the role of the functional side chains in polypeptides and proteins when a metal ion is present, a preliminary investigation of interactions between Cu(II) and l -serine (Ser), l -threonine (Thr), and l - allo -threonine (αThr) has been undertaken. The role of the lateral hydroxyl group was clarified by comparison with O-substituted l -threonine and l -serine. For α-amino-β-hydroxy acids, equilibrium analyses confirmed the formation of the species: Cu-A + , Cu-A 2 , Cu-H − 1 A 2 -, and Cu-H − 2 A 2− (A, any amino acid), and enabled the calculation of the corresponding stability constants in 1 M NaClO 4 (25°C). Visible absorption and circular dichroism measurements lead to the conclusion that, at neutral pH, the ligands maintain their “glycine-like” configuration in Cu-A 2 , which is modified when one proton from each bound ligand dissociates at pH> 9. The N(amino) and O − (hydroxyl) atoms are donors in the coordination square while the O − (carboxyl) donor atom may compete with O(water) for the axial position of Cu(II), leading to a distorted octahedral structure. |
| Databáze: | OpenAIRE |
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