Small-angle x-ray scattering on solutions of carboxymethylcellulose and bovine serum albumin

Abstract

The existence of attractive interaction between CMC and BSA was evidenced in solution at pH higher than the protein isoelectric point by means of SAXS. Mixtures of BSA at 10 × 10-3 g · mL-1 and CMC at the concentration range of 1 × 10-3 g · mL -1 to 10 × 10-3 g · mL-1 were investigated. Upturns in the very low q range revealed the presence of aggregates when the CMC concentration was higher than 2 × 10-3 g · ml-1. The comparison between the calculated form factor with the experimental curves at intermediate and long q values indicated that the BSA molecules keep their native form in mixtures with CMC concentrations lower than 5 × 10-3 g · mL-1. Therefore, for CMC concentrations higher than 2 × 10-3 g · mL -1 the mixtures start to present aggregates and free BSA molecules coexisting in solution. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA.