Capping agents, key for nanoparticle stability, may hugely influence chemical behaviour. We show that differently capped gold nanoparticles, with either citrate or cetyl trimethylammonium bromide (CTAB) capping agents, show qualitatively different electron transfer properties. Specifically through cyclic voltammetry and nanoimpact studies the CTAB promoted dissolution of gold nanoparticles is shown, highlighting the active role which capping agents can play in charge transfer.