| 17429807 |
Karmaker S, Saha TK, Sakurai H: Investigation of a Cu (II)-poly (gamma-glutamic acid) complex in aqueous solution and its insulin-mimetic activity. Macromol Biosci. 2007 Apr 10;7(4):456-66.
The complexation between cupric ions (Cu (II)) and poly (gamma-glutamic acid) (gamma-PGA) in aqueous solutions (pH 3-11) has been studied by UV-visible absorption and electron spin resonance (ESR) techniques. Formation of the Cu (II)-gamma-PGA complex is confirmed by the observation of the blue shift of the absorption band in the visible region, anisotropic line shapes in the ESR spectrum at room temperature, and a computer simulation of the visible absorption spectrum of the complex. The structure of the Cu (II)-gamma-PGA complex, depending on the pH, has been determined. The in vitro insulin-mimetic activity of the Cu (II)-gamma-PGA complex is examined by determining both inhibition of free fatty acid release and glucose uptake in isolated rat adipocytes treated with epinephrine, in which the concentration of the Cu (II)-gamma-PGA complex for 50% inhibition of free fatty acid release is very similar to that of CuSO4. However, it is significantly lower than that of a previously reported insulin-mimetic bis (3-hydroxypicolinato) copper (II), [Cu (3hpic) 2], complex. |
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