cl00285

Aconitase catalytic domain; Aconitase catalyzes the reversible isomerization of citrate and isocitrate as part of the TCA cycle; Aconitase catalytic domain. Aconitase (aconitate hydratase) catalyzes the reversible isomerization of citrate and isocitrate as part of the TCA cycle. Cis-aconitate is formed as an intermediate product during the course of the reaction. In eukaryotes two isozymes of aconitase are known to exist: one found in the mitochondrial matrix and the other found in the cytoplasm. Aconitase, in its active form, contains a 4Fe-4S iron-sulfur cluster; three cysteine residues have been shown to be ligands of the 4Fe-4S cluster. This is the Aconitase core domain, including structural domains 1, 2 and 3, which binds the Fe-S cluster. The aconitase family also contains the following proteins: - Iron-responsive element binding protein (IRE-BP), a cytosolic protein that binds to iron-responsive elements (IREs). IREs are stem-loop structures found in the 5'UTR of ferritin, and delta aminolevulinic acid synthase mRNAs, and in the 3'UTR of transferrin receptor mRNA. IRE-BP also express aconitase activity. - 3-isopropylmalate dehydratase (isopropylmalate isomerase), the enzyme that catalyzes the second step in the biosynthesis of leucine. - Homoaconitase (homoaconitate hydratase), an enzyme that participates in the alpha-aminoadipate pathway of lysine biosynthesis and that converts cis-homoaconitate into homoisocitric acid.