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Specifications

Citrate (isocitrate) hydro-lyase (EC 4.2.1.3)
Catalog #	A0660
	Aconitase (aconitate hydratase; EC 4.2.1.3), 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 4.2.1.33), 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 (25°C, pH 7.4)
State	Highly purified enzyme in solution
	One ml of solution contains the following
	Protein 1~30mg
	Glycerol 50%
	pH 7.0 ± 0.5
Application	Suitable for use as a calibrator or control serum.
Storage and Stability	May be stored at 4°C. For long-term storage, aliquot and store at 4°C. Do not freeze. Aliquots are stable for at least 6 months. 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.