Binding and precipitation of germanium(IV) by penta-O-galloyl-β-d-glucose

The interaction of copper complexed with (−)-epigallocatechin-3-gallate (EGCG) and bovine serum albumin (BSA) was investigated using fluorescence, circular dichroism (CD) spectroscopy, HPLC and protein-ligand docking. The fluorescence quenching efficiency of BSA by EGCG was enhanced after EGCG was complexed with copper, and the EGCG-Cu complex exhibited a higher apparent binding affinity (8.88×105M−1) to BSA compared with EGCG alone (5.17×105M−1). The CD experiment showed that both the EGCG-BSA and [EGCGCu]- BSA interactions resulted in the unfolding of the secondary structure of th Complex formation and precipitation of germanium by a well-characterized hydrolyzable tannin, 1,2,3,4,6-penta-O-galloyl-!-D-glucose (PGG), was studied in this work.