CHES (2-(Cyclohexylamino)ethanesulfonic acid) is a zwitterionic N-substituted aminosulfonic acid. CHES is used as a buffer for studying pH-dependent processes in enzymology. The compound has been shown to have an unusually high affinity for the iodoacetate binding site of liver alcohol dehydrogenase. The compound, which has a has a pKa of 9.49 at 25°C, is useful for the pH 8.6-10.0 range. A zwitterionic buffering agent. CHES has been used: · as a buffer in mannanase activity assay of antarctic fungal isolates · as a buffer for DNA digestion and labeling of 2′-deoxyadenosine 3′-monophosphate · as a component of Wilson and Horne extraction buffer for characterization of rat plasma enzymes