INTERACTION OF DECAVANADATE POLYANIONS WITH PROTEINS

The binding of polymeric decavanadate anion [V10O28](6-) with bovine s erum albumin and gelatin was studied at pH 4.0 and 3.0, the region of thermodynamic stability of oligomeric vanadate anion. The binding of d ecavanadate anion at pH 4.0 with bovine serum albumin (BSA) and gelati n was found to be 9 and 32 gmol of decavanadate per gram mole of the p roteins. The binding at pH 3.0 was found to be 12 and 38 gmol, respect ively. Freshly formed BSA decavanadate precipitate was particulate in nature while that of gelatin-decavanadate made a gummy mass. This indi cates a different mode of binding of decavanadate anions with globular and fibrillar proteins. Infrared spectra of the adducts endorses elec trostatic binding between proteins and decavanadate. Scanning electron microscopy micrographs reveal extended crosslinked binding between de cavanadate and gelatin and aggregation of the uncharged BSA-decavanada te molecules to make a granular adduct. The mode of binding was also c orrelated with the structure of decavanadate anions, BSA, and gelatin. (C) 1995 Academic Press, Inc.