The fractionation of protein mixtures by linear polymers of high molecular weight

The protein fractionating properties of the high molecular weight linear polymers, polyethylene glycol, dextran, nonylphenol-ethoxylate, polyvinyl alcohol and polyvinyl pyrrolidone have been investigated. All were protein precipitants, but varied in selectivity. Polyethylene glycol (mol. wt. 6000) appears to be the most suitable protein precipitants in this group because its solutions are less viscous and cause virtually no denaturation at room temperature. The efficiency of protein fractionation increases with the molecular weight, and therefore chain length, of the polymer. Rapid simple methods for the preparation of γ-globulin and fibrinogen with the aid of polyethylene glycol are described. The products were homogeneous on electrophoresis and centrifugation and retained satisfactory biological properties. © 1964.