Iron-only nitrogenase properties

Molybdenum nitrogenase has been the subject of intensive study for more than 30 years, but much less work has been done on the vanadium and iron-only nitrogenases. Consequently, we first review the properties of Mo nitrogenase, and then in later sections outline what is known of the other two enzymes. 

Again, the enzyme urease was found to contain a dimeric nickel(II) center based only on its magnetic properties (eqn [10] with 5=1). In large proteins such as ferritin, strong coupling is seen in a Fe-O-phosphate center, rather like a small piece of rust enclosed in a protein sheath. Likewise, nitrogenases contain a number of linked irons. 

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