4-Chloromercuribenzoic acid (''p''-chloromercuribenzoic acid, PCMB) is an

organomercury compound Organomercury refers to the group of organometallic compounds that contain mercury. Typically the Hg–C bond is stable toward air and moisture but sensitive to light. Important organomercury compounds are the methylmercury(II) cation, CH3Hg+; et ...

that is used as a protease inhibitor, especially in molecular biology applications. PCMB reacts with

thiol group In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

s in proteins and is therefore an inhibitor of enzymes that are dependent on thiol reactivity, including

cysteine protease Cysteine proteases, also known as thiol proteases, are hydrolase enzymes that degrade proteins. These proteases share a common catalytic mechanism that involves a nucleophilic cysteine thiol in a catalytic triad or dyad. Discovered by Gopal Chund ...

s such as

papain Papain, also known as papaya proteinase I, is a cysteine protease () enzyme present in papaya (''Carica papaya'') and mountain papaya (''Vasconcellea cundinamarcensis''). It is the namesake member of the papain-like protease family. It has wide ...

and

acetylcholinesterase Acetylcholinesterase (HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme Enzymes () are proteins that a ...

. Because of this reactivity with thiols, PCMB is also used in titrimetric quantification of thiol groups in proteins.

References

{{DEFAULTSORT:Chloromercuribenzoic acid, 4- Benzoic acids Organomercury compounds Protease inhibitors

See also

References