Figure 6.

Ca²⁺-dependent dissociation of [³H]ryanodine from the high-affinity binding site of RyR2. Microsomes were incubated with 10 nM [³H]ryanodine in a binding buffer containing 10 μM free Ca²⁺ for 90 min at 37°C to reach equilibrium. The reaction mixes were then incubated for 2 h with different concentrations of EGTA to set the desired pCa values. Duplicate 0.2-ml aliquots were filtered at the time points indicated. The data are normalized to the values obtained after the first 90-min incubation.