[The study of the chemical composition of nitrogenase Fe-Mo-cofactor by a new fluorimetric method of thiocompound analysis].

A purification technique for a large scale production of crystalline Mo-Fe protein of nitrogenase from Azotobacter vinelandii and of its fragment, Fe-Mo-cofactor (Fe-Mo-co) in argon atmosphere has been elaborated. The novel fluorimetric method of thiol compounds analysis has been proposed for identification of Fe-Mo-co thiol ligands; this procedure allows the determination of concentration and class of thiol compounds and of the distance between sulphur atoms in the case of dithiols. The use of this method for an analysis of Fe-Mo-co has demonstrated that it contains a thiomolybdate fragment and two atoms of inorganic sulphur. Organic thiol as a Fe ligand has not been revealed.