Copper solution chemistry of cyclic pseudo-octapeptides

• Verfasst von: Comba, Peter [VerfasserIn]
• Verfasst von: Dovalil, Nina [VerfasserIn]
• Verfasst von: Haberhauer, Gebhard [VerfasserIn]
• Verfasst von: Kowski, Klaus [VerfasserIn]
• Verfasst von: Mehrkens, Nina [VerfasserIn]
• Verfasst von: Westphal, Michael [VerfasserIn]
• Titel: Copper solution chemistry of cyclic pseudo-octapeptides
• Verf.angabe: Peter Comba, Nina Dovalil, Gebhard Haberhauer, Klaus Kowski, Nina Mehrkens, and Michael Westphal
• E-Jahr: 2013
• Jahr: 09 April 2013
• Umfang: 6 S.
• Fussnoten: Gesehen am 04.05.2021
• Titel Quelle: Enthalten in: Zeitschrift für anorganische und allgemeine Chemie
• Ort Quelle: Weinheim : Wiley-VCH, 1892
• Jahr Quelle: 2013
• Band/Heft Quelle: 639(2013), 8/9, Seite 1395-1400
• ISSN Quelle: 1521-3749
• DOI: doi:10.1002/zaac.201300079
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Calorimetry
• Sach-SW: Copper
• Sach-SW: Pseudo-Octapeptides
• Sach-SW: Voltammetry
• K10plus-PPN: 1757091203

Abstract

The CuII solution chemistry of synthetic derivatives of naturally occurring pseudo-octapeptides (patellamides and ascidiacyclamide) is described. The complex stabilities [mono- and dicopper(II) complexes] of five different ligands were determined by isothermal microcalorimetry (ITC), and square wave voltammetry (SQW) was used to elucidate the electrochemical properties. In agreement with published spectroscopic data, there is cooperative binding of two CuII ions and the overall stabilities are, in agreement with known stabilities of the natural ligands and expectations based on the donor sets (two N-based heterocycles and one amide per CuII), only moderate (K ≤ 106). There is a slight dependence of the stabilities on the ligand structure (configuration of the side chains), and that derived from the natural products forms the most stable complexes. Due to the complex equilibria in solution and the instability of the reduced forms, voltammetry shows complex equilibria, which preclude the full assignment of all processes. The positive reduction potentials are in agreement with relatively low complex stabilities. These observations complete earlier studies, concentrating on spectroscopy and structural aspects, and are also discussed in relation to the possible biological function of the cyclic peptides, i.e. metal ion transport, oxygen activation, carboanhydrase, and phosphatase activities.