Ultracentrifugation of hydrated egg lecithin in benzene solution

Estimations of molecular weights from sedimentation equilibrium experiments indicate that the degree of aggregation of egg lecithin in benzene solutions increases with increasing addition of water. The molecular weight rises monotopically from about 14,000 in the anhydrous state to about 57,000 at a water/lecithin ratio of 0.31. Sedimentation coefficients were shown to behave in the same manner. Frictional coefficients obtained from the combined results fail to indicate definite differences in asymmetry; however, they seem to indicate that the aggregates in all stages are compact in shape.