Technical Data
Aconitase, Porcine Heart
Molecular Biology Storage: -20CShipping: Blue Ice
Citrate (isocitrate) hydro-lyase (EC

Aconitase (aconitate hydratase; EC, from pig heart, is an enzyme that catalyses the stereo-specific isomerization of citrate to isocitrate via cis-aconitate in the tricarboxylic acid cycle, a non-redox-active process. By contrast with the majority of iron-sulfur proteins that function as electron carriers, the iron-sulfur cluster of aconitase reacts directly with an enzyme substrate. Aconitase has an active [Fe4S4]2+ cluster, which may convert to an inactive [Fe3S4]+ form. Three cysteine (Cys) residues have been shown to be ligands of the [Fe4S4] centre. In the active state, the labile iron ion of the [Fe4S4] cluster is not coordinated by Cys but by water molecules.

The iron-responsive element binding protein (IRE-BP) and 3-isopropylmalate dehydratase ( -isopropylmalate isomerase; EC, an enzyme catalysing the second step in the biosynthesis of leucine, are known aconitase homologues. Iron regulatory elements (IREs) constitute a family of 28-nucleotide, non-coding, stem-loop structures that regulate iron storage, heme synthesis and iron uptake. They also participate in ribosome binding and control the mRNA turnover (degradation). The specific regulator protein, the IRE-BP, binds to IREs in both 5' and 3' regions, but only to RNA in the apo form, without the Fe-S cluster. Expression of IRE-BP in cultured cells has revealed that the protein functions either as an active aconitase, when cells are iron-replete, or as an active RNA-binding protein, when cells are iron-depleted. Mutant IRE-BPs, in which any or all of the three Cys residues involved in Fe-S formation are replaced by serine, have no aconitase activity, but retain RNA-binding properties.

Aconitase is inhibited by fluoroacetate, therefore fluoroacetate is poisonous. The iron sulfur cluster is highly sensitive to oxidation by superoxide[1].

Standard: Aconitase-05

Specific Activity: 5u/mg protein (25C, pH 7.4)

Suitable for use as a calibrator or control serum.

Storage and Stability:
May be stored at 4C. For long-term storage, aliquot and store at 4C. Do not freeze. Aliquots are stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial prior to removing the cap. Further dilutions can be made in assay buffer.
Source: Porcine Heart
Purity: Highly Purified
Form: Supplied as 50% glycerol solution.

Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.
1. Aconitase: sensitive target and measure of superoxide. Methods Enzymol, 2002. 349: p. 9-23.
2. Beinert, H., Kennedy, M.C. and Stout, C.D. (1996). "Aconitase as iron-sulfur protein, enzyme, and iron-regulatory protein". Chem. Rev. 96: 23352373. doi:10.1021/cr950040z.
3. Flint, D.H. and Allen, R.M. (1996). "Iron-sulfur proteins with nonredox functions". Chem. Rev. 96: 23152334. doi:10.1021/cr950041r.
4. Frishman, D. and Hentze, M.W. (1996). "Conservation of aconitase residues revealed by multiple sequence analysis". Eur. J. Biochem. 239: 197200. doi:10.1111/j.1432-1033.1996.0197u.x.

Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.