Fraction of electron flux that goes to H2 evolution

Value 27.3 % Range: ±2.4 %
Organism Bacteria Azotobacter vinelandii
Reference Orme-Johnson WH. Molecular basis of biological nitrogen fixation. Annu Rev Biophys Biophys Chem. 1985 14: 419-59. p.447 top paragraphPubMed ID3890886
Primary Source Rivera-Ortiz JM, Burris RH. Interactions among substrates and inhibitors of nitrogenase. J Bacteriol. 1975 Aug123(2):537-45.PubMed ID1150625
Comments "The universal observation that H2 is evolved when N2 is the competing substrate has been pursued recently to a definitive conclusion. Simpson & Burris (ref 130) have examined the ratio of H2 evolved to N2 reduced as a function of pN2 up to 50 atmospheres, approximately 360 times the apparent Km for N2 reduction by the Azotobacter nitrogenase preparation employed (primary source). They found that 27.3±2.4 percent of the electron flux went to H2 evolution under conditions where the velocity of N2 reduction is estimated to be 99.7% of maximal."
Entered by Uri M
ID 111319