Aconitase (aconitate hydratase) (EC 22.214.171.124)  is the enzyme from the
tricarboxylic acid cycle that catalyzes the reversible isomerization of
citrate and isocitrate. Cis-aconitate is formed as an intermediary 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
It has been shown that the aconitase family also contains the following
Iron-responsive element binding protein (IRE-BP). IRE-BP is 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 (EC 126.96.36.199) (isopropylmalate isomerase),
the enzyme that catalyzes the second step in the biosynthesis of leucine.
Homoaconitase (EC 188.8.131.52) (homoaconitate hydratase), an enzyme that
participates in the α-aminoadipate pathway of lysine biosynthesis and
that converts cis-homoaconitate into homoisocitric acid.
Esherichia coli protein ybhJ.
As a signature for proteins from the aconitase family we have selected two
conserved regions that contain the three cysteine ligands of the 4Fe-4S
December 2004 / Pattern and text revised.
PROSITE methods (with tools and information) covered by this documentation:
Gruer M.J. Artymiuk P.J. Guest J.R.
The aconitase family: three structural variations on a common theme.
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