The kinetics of the reduction of isocyanides, acetylenes and the cyanide ion by nitrogenase preparation from Azotobacter chroococcum and the effects of inhibitors.
1. Nitrogen-fixing preparations from Azotobacter chroococcum reduced substrates with the following K(m) values: methyl isocyanide, 1.8x10(-4)m; ethyl isocyanide, 2.5x10(-2)m; cyanide ion, 1.4x10(-3)m; acetylene, 1.2x10(-4)m. 2. Nitrogen, carbon monoxide or hydrogen competitively inhibited isocyanide reduction with the following K(i) values: hydrogen, 1.3x10(-3)m; carbon monoxide, 6.8x10(-6)m; nitrogen, 4.3x10(-4)m. 3. Living nitrogen-fixing bacteria, and isolated clover nodules, formed methane from methyl isocyanide. 4. These results are discussed in relation to other work and possible mechanisms of nitrogen fixation.
D001395:Azotobacter / Q000201:enzymology*; D003486:Cyanides / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D007700:Kinetics; D008365:Manometry; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000037:antagonists & inhibitors; D010944:Plants
D003486:Cyanides; D006859:Hydrogen; D010088:Oxidoreductases