title: Resolution of two subunits from the molybdenum-iron protein of Azotobacter vinelandii nitrogenase.
abstract: The Mo-Fe protein of Azotobacter vinelandii nitrogenase was fractionated on 9.5 M urea isoelectric focusing gels and gave three distinct bands (alpha', alpha", beta'). Protein focused on nondenaturing gels gave a single brown band, which when excised and refocused on a denaturing gel gave the three-band pattern. Partial trypsin digestion of the subunits and fractionation of the peptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the alpha' and alpha" polypeptide moieties were the same. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the alpha' and beta' proteins with appropriate molecular weight standards indicated Mr = 61,000 and 57,000, respectively. This is consistent with an overall alpha 2 beta 2 mass of 236,000 daltons.
mesh_terms: D001395:Azotobacter / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D005288:Ferredoxins / Q000302:isolation & purification*; D007525:Isoelectric Focusing; D046911:Macromolecular Substances; D008970:Molecular Weight; D008983:Molybdoferredoxin / Q000302:isolation & purification*; D009591:Nitrogenase / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000032:analysis
chemical_list: D005288:Ferredoxins; D046911:Macromolecular Substances; D008983:Molybdoferredoxin; D010446:Peptide Fragments; D009591:Nitrogenase