Spectroscopic and thermodynamic determination of three distinct binding sites for Co(II) ions in human serum albumin |
| |
Authors: | Magdalena Soko?owska Jaros?aw Poznański Wojciech Bal |
| |
Institution: | a Department of Hygiene, Wroclaw Medical University, Mikulicza-Radeckiego 7, 50-368 Wroclaw, Poland b Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland c Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland d Central Institute for Labour Protection - National Research Institute, Czerniakowska 16, 00-701 Warsaw, Poland |
| |
Abstract: | Human serum albumin (HSA) is the most abundant protein of blood serum, involved in the transport of metal ions, including Co(II). Using circular dichroism spectroscopic titrations we characterized three distinct Co(II) binding sites in HSA. Applying Cu(II), Ni(II) and Cd(II) ions as competitors we determined that these sites are identical with three binding sites known for other metal ions. We ordered these sites according to their binding affinities as cadmium site B (CdB) > multi-metal binding site (MBS) > N-terminal binding site (NTS). Using isothermal titration calorimetry (ITC) we confirmed the presence of these three binding sites and determined their conditional binding constants at pH 7.4 as 9 ± 5, 1.1 ± 0.5, and 0.9 ± 0.3 × 104 M−1, respectively. The impact of these results on the albumin cobalt binding (ACB) clinical assay for myocardial ischemia is discussed. |
| |
Keywords: | Human serum albumin Cobalt(II) Binding constants Isothermal titration calorimetry Circular dichroism |
本文献已被 ScienceDirect 等数据库收录! |
|