4-(Hydroxymercuri)benzoic acid is an organic mercurial compound that reacts via mercury-sulfur affinity with sulfhydryl groups in peptides, proteins and other molecules. PCMB may be used for the determination of sulfhydryl groups in proteins according to Boyer, by atomic absorption, and stopped-flow measurements, G. Castronuovo-Lepore et al.. It may be used for specific applications such as probing the active site of an enzyme such as cytochrome C oxidase. 4-(Hydroxymercuri)benzoic acid appeared mistakenly as p-chloromercuriobenzoate [PCMB] in earlier literature.
