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==Mechanism of Aconitase== | ==Mechanism of Aconitase== | ||
{{STRUCTURE_2b3x | PDB=2b3x | SCENE= }} | {{STRUCTURE_2b3x | PDB=2b3x | SCENE= }} | ||
| + | ====Stage 1: Dehydration==== | ||
Aconitase (PDB [[2b3x]]) catalyzes the reversible isomerization of citrate and isocitrate. First, dehydration of citrate causes a proton and OH group to be removed from only the 'lower arm'.<ref>Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 578. Print.</ref> This forms a cis-Aconitate intermediate. | Aconitase (PDB [[2b3x]]) catalyzes the reversible isomerization of citrate and isocitrate. First, dehydration of citrate causes a proton and OH group to be removed from only the 'lower arm'.<ref>Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 578. Print.</ref> This forms a cis-Aconitate intermediate. | ||
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| + | Aconitase contains 4Fe-4S iron-sulfur cluster. This iron sulfur cluster does not participate in redox as most do, but coordinates the OH goup of citrate to facilitate its elimination.<ref>PMID:16407072 </ref> | ||
| + | ====Stage 2: Rehydration==== | ||
The second main stage of the reaction is the rehydration of the cis-Aconitate intermediate. This forms isocitrate. It is catalyzed in a stereospecific way such that only one isocitrate stereoisomer is formed. <ref>Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 579. Print.</ref> | The second main stage of the reaction is the rehydration of the cis-Aconitate intermediate. This forms isocitrate. It is catalyzed in a stereospecific way such that only one isocitrate stereoisomer is formed. <ref>Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 579. Print.</ref> | ||
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| + | Show mechanism here! | ||
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| + | Thus, the overall reaction that aconitase catalyzes is: | ||
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| + | Show total mechanism here! | ||
Revision as of 01:21, 27 February 2010
Contents |
Mechanism of Aconitase
Stage 1: Dehydration
Aconitase (PDB 2b3x) catalyzes the reversible isomerization of citrate and isocitrate. First, dehydration of citrate causes a proton and OH group to be removed from only the 'lower arm'.[1] This forms a cis-Aconitate intermediate.
Show mechanism here!
Aconitase contains 4Fe-4S iron-sulfur cluster. This iron sulfur cluster does not participate in redox as most do, but coordinates the OH goup of citrate to facilitate its elimination.[2]
Stage 2: Rehydration
The second main stage of the reaction is the rehydration of the cis-Aconitate intermediate. This forms isocitrate. It is catalyzed in a stereospecific way such that only one isocitrate stereoisomer is formed. [3]
Show mechanism here!
Thus, the overall reaction that aconitase catalyzes is:
Show total mechanism here!
References
- ↑ Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 578. Print.
- ↑ Dupuy J, Volbeda A, Carpentier P, Darnault C, Moulis JM, Fontecilla-Camps JC. Crystal structure of human iron regulatory protein 1 as cytosolic aconitase. Structure. 2006 Jan;14(1):129-39. PMID:16407072 doi:10.1016/j.str.2005.09.009
- ↑ Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 579. Print.
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