CAPSO, sodium salt

CAPSO, sodium salt: Molecular Formula: C9H18NO4SNa Molecular Weight: 259.30 The most common buffer for the blotting of proteins to nitrocellulose is the Tris-Glycine buffer (pH 8.3). The transfer of strongly basic proteins is very poor (~20 %). The use of more alkaline transfer buffers (e.g. 25 mM CAPSO, pH 10.0 with 20 % Ethanol or 25 mM AMPSO, pH 9.5) allows for the almost complete transfer of strongly basic proteins from gels to nitrocellulose without lowering the transfer efficiency for other proteins. CAPSO (N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid) sodium salt is used to formulate CAPSO buffer, a zwitterionic buffer that is useful in the range of pH 8.9 – 10.3. CAPSO buffer is used in western and immunoblotting experiments as well as protein sequencing and identification. Used in the electrotransfer of proteins to PVDF or nitrocellulose membranes .The high pH of this buffer makes it useful for the transfer of proteins with a pI > 8.5. CAPSO is not one of the original “Good” buffers, although it has a similar structure to the other propanesulfonic acids and was selected as a highly water soluble buffering reagent with an optimum buffering pH of 10.4 and minimal reactivity with enzymes or proteins, minimal salt effects.