EGTA (chemical)

EGTA (chemical)

Names
IUPAC name ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid
Identifiers
CAS Registry Number	67-42-5 Y
ChEBI	CHEBI:30740 Y
ChEMBL	ChEMBL240390 Y
ChemSpider	5972 Y
InChI InChI=1S/C14H24N2O10/c17-11(18)7-15(8-12(19)20)1-3-25-5-6-26-4-2-16(9-13(21)22)10-14(23)24/h1-10H2,(H,17,18)(H,19,20)(H,21,22)(H,23,24) Y Key: DEFVIWRASFVYLL-UHFFFAOYSA-N Y InChI=1/C10H13NO2/c1-3-13-10-6-4-9(5-7-10)11-8(2)12/h4-7H,3H2,1-2H3,(H,11,12) Key: CPJSUEIXXCENMM-UHFFFAOYAO InChI=1/C14H24N2O10/c17-11(18)7-15(8-12(19)20)1-3-25-5-6-26-4-2-16(9-13(21)22)10-14(23)24/h1-10H2,(H,17,18)(H,19,20)(H,21,22)(H,23,24) Key: DEFVIWRASFVYLL-UHFFFAOYAF
Jmol-3D images	Image
KEGG	D00569 Y
PubChem	6207
SMILES O=C(O)CN(CC(=O)O)CCOCCOCCN(CC(=O)O)CC(=O)O
UNII	526U7A2651 Y
Properties
Molecular formula	C14H24N2O10
Molar mass	380.35 g·mol−1
Melting point	241 °C (466 °F; 514 K)
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

EGTA (ethylene glycol tetraacetic acid) is an aminopolycarboxylic acid, a chelating agent. It is a colourless solid that is related to the better known EDTA. Compared to EDTA, it has a lower affinity for magnesium, making it more selective for calcium ions. It is useful in buffer solutions that resemble the environment in living cells^[1] where calcium ions are usually at least a thousandfold less concentrated than magnesium.

The pKa for binding of calcium ions by tetrabasic EGTA is 11.00, but the protonated forms do not significantly contribute to binding, so at pH 7, the apparent pKa becomes 6.91. See Qin et al. for an example of a pKa calculation.^[2]

EGTA has also been used experimentally for the treatment of animals with cerium poisoning and for the separation of thorium from the mineral monazite. EGTA is used as a compound in elution buffer in the protein purification technique known as tandem affinity purification, in which recombinant fusion proteins are bound to calmodulin beads and eluted out by adding EGTA.

EGTA is often employed in dentistry and endodontics for the removal of the smear layer.

See also

• EDTA
• BAPTA

References

1. ↑ Bett, Glenna C. L.; Rasmusson, Randall L. (2002). "1. Computer Models of Ion Channels". In Cabo, Candido; Rosenbaum, David S. Quantitative Cardiac Electrophysiology. Marcel Dekker. p. 48. ISBN 0-8247-0774-5. 
2. ↑ Ning Qin, Riccardo Olcese, Michael Bransby, Tony Lin, and Lutz Birnbaumer (March 1999). "Ca²⁺-induced inhibition of the cardiac Ca²⁺ channel depends on calmodulin". PNAS 96 (5): 2435–2438. doi:10.1073/pnas.96.5.2435. PMC 26802. PMID 10051660. Retrieved 2007-10-22.