Affordable Access

deepdyve-link
Publisher Website

Revised coordination model and stability constants of Cu(II) complexes of tris buffer.

Authors
  • Nagaj, Justyna1
  • Stokowa-Sołtys, Kamila
  • Kurowska, Ewa
  • Frączyk, Tomasz
  • Jeżowska-Bojczuk, Małgorzata
  • Bal, Wojciech
  • 1 Faculty of Chemistry, University of Wroclaw , Wroclaw, Poland. , (Poland)
Type
Published Article
Journal
Inorganic Chemistry
Publisher
American Chemical Society
Publication Date
Dec 16, 2013
Volume
52
Issue
24
Pages
13927–13933
Identifiers
DOI: 10.1021/ic401451s
PMID: 24304384
Source
Medline
License
Unknown

Abstract

2-Amino-2-hydroxymethyl-propane-1,3-diol, or tris(hydroxymethyl)aminomethane (Tris), is probably the most common biochemical buffer used alone or in combination with other buffers because it is stable, unreactive, and compatible with most proteins and other biomolecules. Being nontoxic, it has even found applications in medicine. Tris is known, however, to coordinate transition metal ions, Cu(II) among them. Although often ignored, this feature affects interactions of Cu(II) ions with biomolecules, as Tris is usually used in high molar excess. Therefore, it is important to have precise knowledge on the stoichiometry, stability, and reactivity of cupric Tris complexes. The literature data are incoherent in this respect. We reinvestigated the complex formation in the Tris-Cu(II) system by potentiometry, UV-vis, ESI-MS, and EPR at a broad range of concentrations and ratios. We found, contrary to several previous papers, that the maximum stoichiometry of Tris to Cu(II) is 2 and at neutral pH, dimeric complexes are formed. The apparent affinity of Tris buffer for Cu(II), determined by the competitivity index (CI) approach [Krężel, A.; Wójcik, J.; Maciejczyk, M.; Bal, W. Chem. Commun. 2003, 6, 704-705] at pH 7.4 varies between 2 × 10(6) and 4 × 10(4) M(-1), depending on the Tris and Cu(II) concentrations and molar ratio.

Report this publication

Statistics

Seen <100 times