Figure 7.

Quantifying intraliposomal Ca²⁺. Initial rates of Na⁺/⁴⁵Ca²⁺ antiport (ΔCPM at 20 s) as a function of external [⁴⁵Ca²⁺]. Liposomes were preloaded with a nominal 50 µM ⁴⁵CaCl₂ and diluted into a buffer with varying ⁴⁵CaCl₂. Internal and external buffers were otherwise symmetric, both with 25 mM NaCl. A triplicate dataset is averaged (error bars represent SEM).