IMPROVEMENT OF THE SOLUBILIZATION OF PROTEINS IN 2-DIMENSIONAL ELECTROPHORESIS WITH IMMOBILIZED PH GRADIENTS

Membrane and nuclear proteins of poor solubility have been separated b y high resolution two-dimensional (2-D) gel electrophoresis. Isoelectr ic focusing with immobilized pH gradients leads to severe quantitative losses of proteins in the resulting 2-D map, although the resolution is usually high. Protein solubility could be improved by using denatur ing solutions containing various detergents and chaotropes. Best resul ts were obtained with a denaturing solution containing urea, thiourea, and detergents (both nonionic and zwitterionic). The usefulness of thi ourea-containing denaturing mixtures is shown for microsomal and nucle ar proteins as well as for tubulin, a protein highly prone to aggregat ion.