Bicinchoninic acid

Bicinchoninic acid
Names
	Preferred IUPAC name [2,2′-Biquinoline]-4,4′-dicarboxylic acid
	Other names Bicinchoninic acid; 4,4′-Dicarboxy-2,2′-biquinoline; 2,2'-Biquinoline-4,4'-dicarboxylic acid
Identifiers
CAS Number	1245-13-2 (free acid) ; 979-88-4 (disodium salt) ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL431482 ;
ChemSpider	64223 ;
ECHA InfoCard	100.013.628
PubChem CID	71068;
UNII	CX56TX9Y1I ;
CompTox Dashboard (EPA)	DTXSID8061638 ;
	InChI InChI=1S/C20H12N2O4/c23-19(24)13-9-17(21-15-7-3-1-5-11(13)15)18-10-14(20(25)26)12-6-2-4-8-16(12)22-18/h1-10H,(H,23,24)(H,25,26) Key: AFYNADDZULBEJA-UHFFFAOYSA-N ;
	SMILES O=C(O)c1cc(nc2c1cccc2)c3nc4ccccc4c(c3)C(=O)O;
Properties
Chemical formula	C20H12N2O4
Molar mass	344.326 g·mol−1
Appearance	Cream colored powder
Odor	Characteristic odor[vague]
Melting point	352 °C (666 °F; 625 K) decomposes
Solubility in water	Partially soluble in cold water, hot water[vague]
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Will irritate eyes and mucous membranes.
NFPA 704 (fire diamond)	1
Safety data sheet (SDS)	External MSDS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Bicinchoninic acid (/baɪsɪnkɔːnɪnɪk/) or BCA is a weak acid composed of two carboxylated quinoline rings. It is an organic compound with the formula (C₉H₅NCO₂H)₂. The molecule consists of a pair of quinoline rings, each bearing a carboxylic acid group. Its sodium salt forms a purple complex with cuprous ions.^[1]^[2]^[3]

Bicinchoninic acid is most commonly employed in the bicinchoninic acid (BCA) assay, which is used to determine the total concentration of protein in a solution. Bicinchoninic acid is used to detect the presence of cuprous ions, due to its purple coloration via a biuret reaction. In this assay, two molecules of bicinchoninic acid chelate a single Cu⁺ ion, forming a purple water-soluble complex that strongly absorbs light at 562 nm.^[4]

References

^ Smith, P.K.; Krohn, R.I.; Hermanson, G.T.; Mallia, A.K.; Gartner, F.H.; Provenzano, M.D.; Fujimoto, E.K.; Goeke, N.M.; Olson, B.J.; Klenk, D.C. (1985). "Measurement of Protein Using Bicinchoninic Acid". Analytical Biochemistry. 150 (1): 76–85. doi:10.1016/0003-2697(85)90442-7. PMID 3843705.
^ Brown, Rhoderick E.; Jarvis, Kari L.; Hyland, Kristi J. (1989). "Protein measurement using bicinchoninic acid: Elimination of interfering substances". Analytical Biochemistry. 180 (1): 136–139. doi:10.1016/0003-2697(89)90101-2. PMID 2817336.
^ Noble, James E.; Bailey, Marc J.A. (2009). "Chapter 8 Quantitation of Protein". Guide to Protein Purification, 2nd Edition. Methods in Enzymology. Vol. 463. pp. 73–95. doi:10.1016/S0076-6879(09)63008-1. ISBN 9780123745361. PMID 19892168.
^ Pierce BCA Protein Assay Kit

[1] Smith, P.K.; Krohn, R.I.; Hermanson, G.T.; Mallia, A.K.; Gartner, F.H.; Provenzano, M.D.; Fujimoto, E.K.; Goeke, N.M.; Olson, B.J.; Klenk, D.C. (1985). "Measurement of Protein Using Bicinchoninic Acid". Analytical Biochemistry. 150 (1): 76–85. doi:10.1016/0003-2697(85)90442-7. PMID 3843705.

[2] Brown, Rhoderick E.; Jarvis, Kari L.; Hyland, Kristi J. (1989). "Protein measurement using bicinchoninic acid: Elimination of interfering substances". Analytical Biochemistry. 180 (1): 136–139. doi:10.1016/0003-2697(89)90101-2. PMID 2817336.

[3] Noble, James E.; Bailey, Marc J.A. (2009). "Chapter 8 Quantitation of Protein". Guide to Protein Purification, 2nd Edition. Methods in Enzymology. Vol. 463. pp. 73–95. doi:10.1016/S0076-6879(09)63008-1. ISBN 9780123745361. PMID 19892168.

[4] Pierce BCA Protein Assay Kit

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