Highly Selective Rapid Calcium Chelators
BAPTA and BAPTA-Na4 are highly selective chelators for Ca2+ over Mg2+.1,2) BAPTA and BAPTA-Na4 are EGTA derivatives whose carbon chains between oxygen and nitrogen atoms are replaced with benzene rings. Their selectivity for Ca2+ is higher than EGTA’s and the binding does not depend on pH. Their chelation reactions are more rapid than that of EGTA, thus, it has been reported that the distances between Ca2+ channels and Ca2+ sensors in neurons can be evaluated by analyzing the transmitter release inhibition by different chelators.3) While both BAPTA and BAPTA-Na4 are membrane-impermeable, BAPTA-AM, a BAPTA ester, is membrane-permeable and can chelate with Ca2+ in cells after the hydrolysis by intracellular esterases.4) In this way, BAPTA, BAPTA-Na4 and BAPTA-AM are valuable tools to study the role of calcium in cell signaling.
- 1) New calcium indicators and buffers with high selectivity against magnesium and protons: design, synthesis, and properties of prototype structures
- 2) Preparation of solutions with free calcium concentration in the nanomolar range using 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (a review)
- 3) Nanodomain coupling between Ca2+ channels and Ca2+ sensors promotes fast and efficient transmitter release at a cortical GABAergic synapse
- 4) A non-disruptive technique for loading calcium buffers and indicators into cells