Detection and quantitation of radiolabeled proteins and DNA in gels and blots.

This unit presents procedures for visualizing and quantitating radiolabeled proteins or DNA separated by polyacrylamide gel electrophoresis (PAGE) or affixed to filter membranes. Procedures for autoradiography and densitometry are provided, but even greater sensitivity can be achieved with fluorography or by the use of intensifying screens, both of which enhance the radioactive signal. Preflashing the film is described to increase the linear measurement range for weakly radioactive samples. Sensitivity and linear ranges of measurement can also be greatly extended by using a phosphor imaging system to quickly and easily quantify radioactive samples.