LIGHT-SCATTERING AND SEDIMENTATION STUDIES OF BOVINE SERUM ALBUMIN AT LOW pH

Light-scattering measurements of bovine serum albumin made at pH 1.9 in 0.1 M-0.45 M potassium chloride show that the molecule is not dissociated, but has the same molecular weight as in neutral solution. At pH 1.9 in the absence of salt aggregation occurs, the extent increasing with time. The sedimentation constant at pH 1.9 increases from 3.2S in 0.1 M potassium chloride to 3.6 in the 0.5 M salt, compared with 4.3 in neutral solution. These differences are ascribed to changes of molecular shape.