Improved detection of calcium-binding proteins in polyacrylamide gels.

We refined the method of Schibeci and Martonosi (1980a) to enhance detection of calcium-binding proteins in polyacrylamide gels using 45Ca2+. Our efforts have produced a method which is shorter, has 40-fold greater sensitivity over the previous method, and will detect 'EF hand'-containing calcium-binding proteins in polyacrylamide gels below the 0.5 microgram level. In addition, this method will detect at least one example from every described class of calcium-binding protein, including lectins and gamma-carboxyglutamic acid containing calcium-binding proteins. The method should be useful for detecting calcium-binding proteins which may trigger neurotransmitter release.