Binding equilibrium study between Mn(II) and HSA or BSA

✍ Scribed by Liang Hong; Tu Chu-Qiao; Zhang Hong-Zhi; Shen Xing-Can; Zhou Yong-Qia; Shen Pan-Wen

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 448 KB
• Volume: 18
• Category: Article
• ISSN: 0256-7660
• DOI: 10.1002/cjoc.20000180107

✦ Synopsis

Abstract

The binding of Mn(II) to human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by equilibrium dialysis at physiological pH (7.43). The Scatchard analysis indicates that there are 1.8 and 1.9 strong binding sites of Mn(II) in HSA and BSA, respectively. The successive stability constants which are reported for the first time are obtained by non‐linear least‐squares methods fitting Bjerrum formula. For both Mn(II)‐HSA and Mn(II)‐BSA systems, the order of magnitude of K~1~ was found to be 10^4^. The analyses of Hill plots and free energy coupling show that the positive cooperative effect was found in bom Mh(II)‐HSA and Mn(II)‐BSA systems. The results of Mn (II) competing with Cu (II) Zn(II), Cd(II) or Ca(II) to bind to HSA or BSA further support the conjecture that there are two strong binding sites of Mn(II) in both HSA and BSA. One is most probably located at the tripeptide segment of N‐terminal sequence of HSA and BSA molecules involving four groups composed of nitrogen atoms, and the fifth coordination atom is the carboxyl oxygen of Asp^1^. The coordinated atoms of the other are most probably almost all oxygen atoms.