Fig. 9. Effect of intravesicular OH^– concentration on ³⁵SO₄^2– influx at 5 mmol l^–1 (A) and 10 mmol l^–1 SO₄^2– (B) (5 s uptakes) in hepatopancreatic LMV. In both cases the extravesicular pH was held at 7.0. Vesicles were loaded with 200 mmol l^–1 mannitol and either 20 mmol l^–1 Hepes/Tris or Mes/Tris, pH 7.0, 8.0 and 9.0. Loaded vesicles were then incubated in media containing either 5 or 10 mmol l^–1 K₂³⁵SO₄, 20 mmol l^–1 Hepes/Tris, pH 7.0 and mannitol to maintain osmolarity. The experiment was repeated in triplicate; values are means ± 1 s.e.m. The hyperbolic curves drawn through the data using Sigma Plot software (Jandal).