I am working with cell wall protein of Candida albicans and cryptococcus neoformans but after protein extraction and run on SDS PAGE my bands are not visible after coomassie staining. Can anyone tell me how to concentrate the protein so that bands can be seen on coomassie stain. I am using Ammonium Carbonate buffer for extraction of protein. Also, the bands are visible on silver staining.
The problem here is concentration. Coomassie Blue stain can only detect protein band greater than or near to 50ng, in this case, the concentration of your protein is too low for detection. If you want to stick with Coomassie stain, you can try colloidal Coomasie stain instead because it has a much lower detection limit than Coomasie blue (between 10ng to 20ng).
In addition, I think what causes such low protein concentration is the poor solubility of yeast cell wall. One way to get around this is to increase solubility is through chemical hydrolysis, for example using diluted sulphuric acid1-3. This will partially solubilize mannas-protein outer layer of the cell wall and help you to obtain soluble yeast cell wall products.
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