Finally, we have shown, that RHR proceeds at a constant rate in a wide pH range (7.5-10) with a slight optimum at pH 9.0. Based on our preliminary pre-steady state it seems that OHR with DCPIP is slower than RHR and as a result, is controlling the steady-state kinetics and determining a steady-state pH optimum at 6.5. Unfortunately, unlike KstD1 from R.