[Na⁺]-dependence of L-[³H]-glutamate into arsenite-treated (uninfected) human erythrocytes. The cells were suspended in a solution containing choline chloride + NaCl at a combined concentration of 150mM, together with 20mM sucrose and 10mM Tris-HCl (pH 7.4). Uptake of L-[³H]-glutamate was measured for 10 minutes at 37°C. The fitted line is a rectangular hyperbola (v = v_max [Na⁺]/(B + [Na⁺])) with B, the [Na⁺] at which uptake is half-maximal, 11.7 ± 1.8mM. The data were averaged from 5 independent experiments, ± SEM.