Fig. 6.

Charge:peptide stoichiometry of uptake of Gly-l-Gln in Xenopus oocytes expressing R282E-, R282D- or R282A-PepT1, normalised to that of the wild-type PepT1 being 1:1 as previously reported (Fei et al., 1994; Steel et al., 1997). The average error on the current measurements was 13 ± 3.8% (n = 3 oocytes per mutant) and on the uptakes 4.4 ± 0.7% (n = 5 oocytes per mutant); the error bars on the figure represent the extremes of the stoichiometry that would be calculated using these error values.