Representive traces of PepT1 overexpressed in CHO cells. PepT1 (SLC15A1) is expressed mainly in intestine and kidney, it enables uptake of oligopeptides. The PepT1 signal is evoked by glycylglycin. The transport of oligopeptides can be inhibited by addition of Lys[Z(NO2)]-Val. The IC50 of Lys[Z(NO2)]-Val was 380µM.