Development and mechanisms of silver stains for electrophoresis

Abstract

Silver stains permit the detection of nanogram amounts of proteins and nucleic acids in gels or membranes. These silver stains have been adapted from histological and photographic photochemical protocols. The basic mechanism of the visualization of protein and nucleic acids by silver staining involves the reduction of ionic to metallic silver. Staining properties of individual amino acids, homopolymers, and small peptides, have been used to demonstrate the importance of the basic amino acids, lysine and histidine, and the sulfur containing amino acids in the silver staining of proteins while the purines have proven to be important in the staining of nucleic acids. Many silver stains demonstrate reproducible curvilinear relationships between silver densities and protein and nucleic acid concentrations. Their sensitivity and reproducibility permits their use in quantitative analysis. By utilizing sets of operationally con stitutive proteins for the normalization of intra-gel stain intensities, quantitative comparisons of protein concentrations have been made in electrophoretograms from complex biological fluids or cellular extracts. These ultrasensitive silver stains have also permitted the discovery of disease associated spinal fluid proteins in a number of central nervous system diseases. © 1986, JAPAN SOCIETY OF HISTOCHEMISTRY AND CYTOCHEMISTRY. All rights reserved.