Multiple forms of cytoplasmic ER and PgR characterized by polyacrylamide gel electrophoresis.

The multiple forms of cytoplasmic ER and PgR were electrophoretically characterized by PAGE under non-denatured conditions and SDS PAGE under denatured conditions. The ordinary PAGE and SDS PAGE were modified in such a way as to reveal the authentic multiple forms of the hormone receptors studied. The experimental conditions were well-defined. The standard protein criteria for evaluation of molecular weights were established. The high polymers containing main activity can be revealed by 3% PAGE under non-denatured conditions and all the multiple forms can be revealed by 3% SDS PAGE under milder SDS coupling reaction. The multiple forms commonly occurring are monomer, dimer, tetramer and hexamer for both ER and PgR. For PgR, there are two monomer components A and B, dimer AB. Tetramer 2AB and hexamer 3 AB. Octamer 4 AB is observed sometimes.