Biological Activation of Heteropoly Complex of Molybdotungstosilicate Containing Lanthanum K10H3La(SiMo6W5O39)226H2O: Spectroscopic Approach and Microcalorimetry

• Published in: Biological trace element research 2010-06, Vol.135 (1-3), p.314
• Main Authors: Hu, Yan-jun, Ou-yang, Yu, Zhao, Ru-ming, Liu, Yi
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Binding sites; Biology; E coli; Energy transfer; Fluorescence; Lanthanum; Spectrum analysis
• ISSN: 0163-4984; 1559-0720
• DOI: 10.1007/s12011-009-8493-8

In this paper, the biological activation of heteropoly complex of molybdotungstosilicate containing lanthanum K^sub 10^H^sub 3^La(SiMo^sub 6^W^sub 5^O^sub 39^)^sub 2^26H^sub 2^O (LaW^sub 5^) was investigated by spectroscopic approach and microcalorimetry under the human physiological conditions. Fluorescence spectroscopy in combination with UV-Vis absorption spectroscopy was employed to investigate the binding of LaW^sub 5^ to bovine serum albumin (BSA). In the mechanism discussion, it was proved that the fluorescence quenching of BSA by LaW^sub 5^ is a result of the formation of LaW^sub 5^-BSA complex. Binding parameters were determined using the Stern-Volmer equation. The results of thermodynamic parameters [increment]G, [increment]H, [increment]S at different temperatures indicate that van der Waals interactions and hydrogen bonds play a major role for LaW^sub 5^-BSA association. The distance r between donor (BSA) and acceptor (LaW^sub 5^) was obtained according to fluorescence resonance energy transfer. Furthermore, the calorimetric method was used to monitor the biological activity of LaW^sub 5^ in Escherichia coli.[PUBLICATION ABSTRACT]