Redox-dependent activation of CO dehydrogenase from Rhodospirillum rubrum

Abstract

Studies of initial activities of carbon monoxide dehydrogenase (CODH) from Rhodospirillum rubrum show that CODH is mostly inactive at redox potentials higher than -300 mV. Initial activities measured at a wide range of redox potentials (0-500 mV) fit a function corresponding to the Nernst equation with a midpoint potential of -316 mV. Previously, extensive EPR studies of CODH have suggested that CODH has three distinct redox states: (i) a spin-coupled state at -60 to -300 mV that gives rise to an EPR signal termed Cred1; (ii) uncoupled states at