Silver Staining Kit is an extremely sensitive color-imetric staining procedure for the detection ofsubnanogram amounts of proteins resolved onpolyacrylamide gels. With high sensitivity andvery low background, Silver Staining Kit is idealfor the visualization of protein bands in dilutesamples or for the detection of proteins presentin trace amounts. It is generally about 100 foldmore sensitive than the commonly used CoomassieBlue stain.The 4 hour staining procedure begins witha fixation step to reduce band diffusion and removeinterfering substances. A sensitization process,which enhances binding of silver ions to proteins,follows fixation. The staining step allows silver ionsto permeate the gel and bind preferentially tosulfhydryl and carboxyl side chains. In the finaldevelopment step,silver ions are reduced to metallicsilver to form precipitates that are visible as brownbands within the gel. Staining intensity varies by thetype of protein in the sample. Acidic proteins andproteins with highly negatively charged sulfatedsugar residues such as proteoglycans and mucinsare not readily detected by silver stains.