Evaluation of viscosities of aqueous two-phase systems containing protein

The dynamic viscosities of aqueous polyethylene glycol, aqueous bovine serum albumin, and polyethylene glycol–bovine serum albumin–water solutions were measured at temperatures of 15, 20, 25, 30 and 35 °C. To estimate the viscosity values of polyethylene glycol–bovine serum albumin–water solutions, a one parameter Grunberg-like model which was satisfactorily used earlier by the present author for polyethylene glycol-dextran–water solutions was employed. The disposable parameter a for our temperature range was estimated as 3.71. The relative errors varying from 0.29 to 18.98 in absolute value indicates that the Grunberg-like model works perfectly for polymer-protein solutions as well.