4-Chloromercuribenzoic acid

4-Chloromercuribenzoic acid^[1]

Names
IUPAC name (4-Carboxyphenyl)chloromercury
Other names p-Chloromercurybenzoic acid; p-Chloromercuribenzoate; 4-Chloromercuribenzoate
Identifiers
CAS Number	59-85-8
Abbreviations	PCMB
ChEBI	CHEBI:28420
ChEMBL	ChEMBL575867
ChemSpider	1667
Jmol interactive 3D	Image
PubChem	1730
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 Key: YFZOUMNUDGGHIW-UHFFFAOYSA-M 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
SMILES O=C(O)c1ccc([Hg]Cl)cc1
Properties
Chemical formula	C7H5ClHgO2
Molar mass	357.16 g·mol^−1
Melting point	287 °C (549 °F; 560 K) (dec.)
Hazards
R-phrases	R26/27/28 R33 R50/53
S-phrases	S13 S28 S36 S45 S60 S61
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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

1. 4-Chloromercuribenzoic acid at Sigma-Aldrich