Isolation of thiomolybdate compounds from the molybdenum-iron protein of clostridial nitrogenase.

Acid/base treatment of the molybdenum-iron protein of the nitrogenase from Clostridium pasteurianum 25 yields low-molecular-weight compounds of molybdenum, which can be separated from the protein by gel chromatography. Elementary analysis and spectral properties relate these compounds to thiomolybdate anions. It is proposed that in its native state nitrogenase contains a thio complex of molybdenum coupled to iron-sulfur clusters.