Figure 4 : Electrometric sensor traces for H+-pumping.

From: Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism

Figure 4

Traces obtained for VrPPase from the Nanion SURFE2R N1 machine. (a) Effect of increasing concentrations of K4PPi and K2HPO4 on signal amplitude of VrPPase proteoliposomes. (b) Effect of etidronate addition to K4PPi-induced signals of VrPPase proteoliposomes. (c) Effect of K4PPi and IDP on liposomes without pyrophosphatase. (d) Effect of IDP on amplitude in the presence and absence of gramicidin compared with K2HPO4. (e) Effect of etidronate addition to IDP-induced signals of VrPPase proteoliposomes. (f) Effect of etidronate on amplitude in the presence and absence of gramicidin compared with K2HPO4. Activating buffer containing substrate or inhibitor was added at 1 s and removed at 2 s. Two anomalous peaks (covering <0.01 s) were removed from e for the sake of clarity.