Table 19.7 Ca2+ affinities of BAPTA chelators.

Chelator Water-Soluble Salt Cell-Permeant Ester Kd for Ca2+
BAPTAB1204, B1212, B1214B1205, B6769No Mg2+: 160 nM *
1 mM Mg2+: 700 nM †
5,5'-Dibromo BAPTAD1211NANo Mg2+: 1.6 µM ‡
5,5'-Difluoro BAPTANAD1209No Mg2+: 635 nM §
1 mM Mg2+: 705 nM §
5,5'-Dimethyl BAPTANAD1207No Mg2+: 40 nM ‡
* Measured in 10 mM MOPS, 100 mM KCl, pH 7.2 at 22°C. † Measured in 10 mM HEPES, 300 mM KCl, pH 7.0 at 22°C.ref ‡ Measured in 10 mM MOPS, 100 mM KCl, pH 7.3 at 22°C.ref § Measured in 10 mM HEPES, 115 mM KCl, 20 mM NaCl, pH 7.05.ref NA = Not available.
For Research Use Only. Not for use in diagnostic procedures.