ELA2

Ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) is a chelating agent that is widely used in biochemistry and molecular biology. It is a derivative of ethylenediaminetetraacetic acid (EDTA) and is particularly notable for its ability to bind calcium ions with high specificity.

Chemical Structure and Properties

EGTA is a polyamino carboxylic acid with the chemical formula C₁₄H₂₄N₂O₁₀. It is a white, crystalline powder that is soluble in water. The molecule contains two ethylene glycol units, which provide flexibility, and four carboxylate groups that are responsible for its chelating properties.

Calcium Binding

EGTA has a high affinity for calcium ions (Ca²⁺) and is often used to sequester calcium in biological experiments. The binding of calcium by EGTA is pH-dependent, with optimal binding occurring at a pH of around 7.0 to 8.0. This makes EGTA particularly useful in experiments where precise control of calcium ion concentration is required.

Applications in Biochemistry

EGTA is commonly used in the preparation of buffer solutions to control calcium ion concentrations in cell culture and biochemical assays. It is also used in electrophysiology to study calcium-dependent processes in cells.

Role in Calcium Signaling

In cellular biology, calcium ions play a crucial role as a second messenger in signal transduction pathways. EGTA is used to modulate calcium levels in cells, allowing researchers to study the effects of calcium on cellular processes such as muscle contraction, neurotransmitter release, and enzyme activity.

Use in Protein Purification

EGTA is also employed in the purification of proteins that require the removal of calcium ions to maintain stability or activity. By chelating calcium, EGTA can prevent unwanted interactions and aggregation of proteins during purification processes.

Comparison with EDTA

While both EGTA and EDTA are chelating agents, EGTA is more selective for calcium ions over magnesium ions (Mg²⁺) compared to EDTA. This selectivity makes EGTA particularly useful in experiments where it is important to distinguish between the effects of calcium and magnesium.

Safety and Handling

EGTA is generally considered safe to handle in laboratory settings, but it should be used with appropriate safety precautions. It is important to avoid inhalation and contact with skin and eyes. As with all chemicals, proper disposal procedures should be followed.

Also see

• Chelation therapy
• Calcium signaling
• Buffer solution
• Ethylenediaminetetraacetic acid