<p>A number of enzymes have been shown to be functionally as well asevolutionary related [<cite idref="PUB00002139"/>]. The nifV and leuA genes encode homocitrate synthase and alpha-isopropylmalate synthase, respectivelyThe N-terminal parts of NifV and LeuA from bacteria are highly similar to each other [<cite idref="PUB00006373"/>]. Homocitrate synthase (<db_xref db="EC" dbkey="2.3.3.14"/>) (gene nifV) is involved in the biosynthesis of the iron-molybdenum cofactor of nitrogenase and catalyzes the condensation of acetyl-CoA and alpha-ketoglutarate into homocitrate. Alpha-isopropylmalate synthase (<db_xref db="EC" dbkey="2.3.3.13"/>) catalyses the first step in the biosynthesis of leucine, the condensation ofacetyl-CoA and alpha- ketoisovalerate to form 2-isopropylmalate synthase.</p>