H2 formation from the E2–E4 states of nitrogenase
Nitrogenase is the only enzyme that can cleave the strong triple bond in N2, making nitrogen available for biological lifeforms. The active site is a MoFe7S9C cluster (the FeMo cluster) that binds eight electrons and protons during one catalytic cycle, giving rise to eight intermediate states E0–E7. It is experimentally known that N2 binds to the E4 state and that H2 is a compulsory biproduct of t