4-Chloromercuribenzoic acid

4-Chloromercuribenzoic acid[1]
IUPAC name (4-Carboxyphenyl)chloromercury
Other names p-Chloromercurybenzoic acid; p-Chloromercuribenzoate; 4-Chloromercuribenzoate
Identifiers
Abbreviations	PCMB
CAS number	59-85-8 Y
PubChem	1730
ChemSpider	1667 Y
ChEBI	CHEBI:28420 Y
ChEMBL	CHEMBL575867 Y
Jmol-3D images	{{#if:O=C(O)c1ccc([Hg]Cl)cc1|Image 1
SMILES O=C(O)c1ccc([Hg]Cl)cc1
InChI InChI=1S/C7H5O2.ClH.Hg/c8-7(9)6-4-2-1-3-5-6;;/h2-5H,(H,8,9);1H;/q;;+1/p-1 Y Key: YFZOUMNUDGGHIW-UHFFFAOYSA-M Y InChI=1/C7H5O2.ClH.Hg/c8-7(9)6-4-2-1-3-5-6;;/h2-5H,(H,8,9);1H;/q;;+1/p-1/rC7H5ClHgO2/c8-9-6-3-1-5(2-4-6)7(10)11/h1-4H,(H,10,11) Key: YFZOUMNUDGGHIW-PSWPUYSSAS
Properties
Molecular formula	C7H5ClHgO2
Molar mass	357.16 g mol−1
Melting point	287 °C (dec.)
Hazards
R-phrases	R26/27/28 R33 R50/53
S-phrases	S13 S28 S36 S45 S60 S61
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

4-Chloromercuribenzoic acid (p-chloromercuribenzoic acid, PCMB) is an organomercury compound that is used as a protease inhibitor, especially in molecular biology applications.

PCMB reacts with thiol groups in proteins and is therefore an inhibitor of enzymes that are dependent on thiol reactivity, including cysteine proteases such as papain and acetylcholinesterase. Because of this reactivity with thiols, PCMB is also used in titrimetric quantification of thiol groups in proteins.

References