Fig. 5

Time-dependent filling of SR vesicles and exposure to 1,2-DCB. In order to determine the effect of 1,2-DCB on the filling of the vesicles by SERCA protein, we exposed on the SR membrane, ⁴⁵Ca²⁺ uptake was measured under same conditions described for Ca²⁺ transport. At different times in Ca²⁺ uptake, 1,2-DCB (open circles) was added to the reaction media before stopping the reaction. The same reaction without DCB treatment was tested as a control (closed circles). Two additional positive controls were incorporated in substitution for oxalate, Ca²⁺ ionophore (1.5 μM of A23187) was added to the assays with (closed triangles) or without 1 mM 1,2-DCB (open triangles). Very importantly, A23187 did not allow Ca²⁺ to be accumulated into SR vesicles