This work continues our examination of the contribution of protein charge to partitioning in polyethylene glycol-dextran aqueous two-phase systems. The partitioning of T4 lysozyme and its charge-change mutants, both point mutations and fusion tails, in aqueous two-phase systems with NaCl, KCl, K2SO4, and potassium phosphate salts at concentrations from ca. 0.05-0.5 M are reported. Both salts and proteins have different distributions in systems with the same overall polymer concentration but different salts and salt concentrations. T4 lysozyme point mutants and fusion-tail mutants of the same charge display different partitioning behaviors. The paint mutation mutants were best suited for distinguishing nonelectrostatic from electrostatic effects of the different salts on protein partitioning.