Silver Staining - (Jan/26/2006 )
Does anybody know the roles of the different compounds acting in silver staining?
i have never been able to find any definitive explanations on how, step by step, silver staining works. here is my best guess for Blum's Silver Stain Method:
Fixative and Rinse: gets rid of loading buffer and precipitates protein into acrylamide matrix. Rinse gets rid of acid and alcohols used in fixitive.
Sensitizer: this one is ambiguous. i assume the sodium thiosulfate (Na2S2O3) sensitizes the protein for the next chemical step. the ambiguous part is if it is a redox reaction on the backbone only, specific sidechains only, or both. sodium sulfite is used in photography developing as an oxygen scavanger. so maybe that's also what this does and doesn't react with the protein at all.
Silver Nitrate: the silver attaches to, again ambigous, backbone and/or sidechains of the protein
Developer: the reductant formaldehyde reacts with the silver to make it unsoluble and deposits the reduced silver metal in the matrix. the sodium carbonate may be to keep the solution alkaline and/or mop up any unused cations. and the sodium thiosulfate reacts with any extra silver in solution and prevent further reaction.
Stop Solution: neutralizes alkaline solution and stops the reaction
hope that helps. i don't know if any of this is true, this is what i have worked out in my tiny brain. anybody else out there believe this?