Advances in biological nitrogen fixation (Reprinted from Developments in Industrial Microbiology, vol 19, pg 1-13, 1978)

Recent work on the biochemistry of N-2 fixation including evidence supporting the current concept of electron transfer in N-2 fixation is discussed. MgATP combines specifically with the Fe protein of nitrogenase, and lowers its potential sufficiently (near -400 my) so that it can reduce the MoFe protein of nitrogenase. The MoFe protein serves as an electron sink to reduce all nitrogenase substrates. The potential loss of energy via release of H-2 is discussed. There is a marked homology among the nitrogenase components from diverse sources, but the components from Clostridium pasteurianum often do not form catalytically active complexes with components from other organisms. The Fe protein from C. pasteurianum and the MoFe protein from Azotobacter vinelandii form a tightly binding, catalytically inactive complex.