Hydrodynamic properties of a– globulin from Sesamum indicum L.

ABSTRACT

The protein α-globulin from Sesamum indicum L. has been characterised for its size and shape using various chemical, physico-chemical and hydrodynamic properties. The protein has an S of 12·8, D 20,w of 4·9 × 10-7 cm2/sec and a partial specific volume of 0·725 ml/g in the native state. The intrinsic viscosity of the protein was determined to be 3·0 ml/g indicating it to be globular in shape. The molecular weight of the protein as determined by various approaches in analytical ultracentrifugation varies from 2·6–2·74 × 105. The molecular weight from sedimentation equilibrium yields a value of 2·74 × 105 in the native state and a value of 19000 in the dissociated and denatured state in 6 Μ guanidine hydrochloride. The evaluation of frictional ratios using Stokes radius and results from electron microscopy confirms the protein to be globular in shape. The protein consists of at least 12–14 subunits. The evaluation of hydrophobic parameters and energetics of interaction of subunits indicate that the protein is stabilized predominantly by hydrophobic interactions.