Fig. 2.

Transport activity and pH dependence of zebrafish PepT1a (Slc15a1a) and PepT1b (Slc15a1b). a Representative traces of transport currents in zebrafish PepT1a (zfPepT1a, top) and zebrafish PepT1b (zfPepT1b, bottom) heterologously expressed in Xenopus laevis oocytes. The currents in the presence of the substrates (1 mmol/L), indicated by bars, were recorded at the holding potential of − 60 mV and at pH 6.5 (left), 7.6 (middle), and pH 8.5 (right). b Transport-associated currents elicited by 1 mmol/L Gly-Gln (GQ) (left), Ala-Ala (AA) (middle), and Gly-Gly-Gly (GGG) (right) at − 60 mV at pH 6.5 (green), 7.6 (blue), and 8.5 (orange). Current values, shown in the histograms as the differences of the current recorded in the presence of the substrate and that in its absence, are reported as means ± SEM from 5 oocytes from 1 batch (one-way ANOVA test; *P < 0.05, **P < 0.01, and ***P < 0.001)