Fig. 9. Effect of inside-negative vesicular interior on (A) [¹⁴C]oxalate/Cl^– exchange and (B) ³⁶Cl^–/Ox^2– exchange in hepatopancreatic BBMV. (A) Vesicles were preloaded with 100 mmol l^–1 KCl and 100 mmol l^–1 TMA-gluconate and incubated in media containing 0.1 mmol l^–1 [¹⁴C]oxalate and either 100 mmol l^–1 K-gluconate and 100 mmol l^–1 TMA-gluconate (open bar) or 200 mmol l^–1 TMA-gluconate (hatched bar). (B) Vesicles were preloaded with 50 mmol l^–1 K₂SO₄ and 75 mmol l^–1 TMA-gluconate and incubated in media containing 10 mmol l^{–1 36}Cl^– and either 100 mmol l^–1 K-gluconate and 100 mmol l^–1 TMA-gluconate (open bar) or 200 mmol l^–1 TMA-gluconate (hatched bar). All media contained 40 mmol l^–1 Hepes-Tris at pH 7.0.