Simultaneous detection of 35S- and 32P-labeled proteins on electrophoretic gels

A simple technique for the direct autoradiographic detection of 35S and 32P isotope emissions has been applied to the analysis of cellular proteins separated by two-dimensional gel electrophoresis. Two films were exposed simultaneously; one recorded directly the β emissions from 35S and the other (shielded by aluminum foil 0.015 mm thick) recorded scintillation photons from an intensifying screen excited by the 32P emissions. At room temperature there was considerable exposure of the 35S film by 32P emissions (20% of that detected on the 32P film). However, at low temperature (−80°C) there was no detection of 35S on the 32P film and only 5% of the β emissions detected on the 32P film exposed the 35S film.