CAPSO buffer is a zwitterionic buffer used in western and immunoblotting, as well as in protein sequencing and identification. CAPSO is also 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. CAPS buffer has very low metal-binding constants and are, therefore, particularly suited to investigate metal-dependent enzymes. CAPSO is selected as a highly water soluble buffering reagent with an optimum buffering pH of 10.4 and minimal reactivity with enzymes or proteins with minimal salt effects.
