MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion Type Simple Reactions Chemical Reactions Protein-Modification Reactions
Reactions Classified By Substrate Macromolecule Reactions Protein-Reactions Protein-Modification Reactions

EC Number:

Enzymes and Genes:

Escherichia coli K-12 substr. MG1655 : 3-hydroxy-acyl-[acyl-carrier-protein] dehydratase Inferred from experiment : fabZ

In Pathway: palmitoleate biosynthesis I (from (5Z)-dodec-5-enoate)

Supersedes EC numbers:,,

Note that this reaction equation differs from the official Enzyme Commission reaction equation for this EC number, which can be found here .

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

Mass balance status: Balanced.

Enzyme Commission Primary Name: 3-hydroxyacyl-[acyl-carrier-protein] dehydratase

Enzyme Commission Synonyms: fabZ (gene name), fabA (gene name), D-3-hydroxyoctanoyl-[acyl carrier protein] dehydratase, D-3-hydroxyoctanoyl-acyl carrier protein dehydratase, β-hydroxyoctanoyl-acyl carrier protein dehydrase, β-hydroxyoctanoyl thioester dehydratase, β-hydroxyoctanoyl-ACP-dehydrase, (3R)-3-hydroxyoctanoyl-[acyl-carrier-protein] hydro-lyase, (3R)-3-hydroxyoctanoyl-[acyl-carrier-protein] hydro-lyase (oct-2-enoyl-[acyl-carrier protein]-forming), 3-hydroxyoctanoyl-[acyl-carrier-protein] dehydratase

Standard Gibbs Free Energy (ΔrG in kcal/mol): 22.705242 Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
This enzyme is responsible for the dehydration step of the dissociated (type II) fatty-acid biosynthesis system that occurs in plants and bacteria. The enzyme uses fatty acyl thioesters of ACP in vivo. Different forms of the enzyme may have preferences for substrates with different chain length. For example, the activity of FabZ, the ubiquitous enzyme in bacteria, decreases with increasing chain length. Gram-negative bacteria that produce unsaturated fatty acids, such as Escherichia coli, have another form (FabA) that prefers intermediate chain length, and also catalyses EC, trans-2-decenoyl-[acyl-carrier protein] isomerase. Despite the differences both forms can catalyse all steps leading to the synthesis of palmitate (C16:0). FabZ, but not FabA, can also accept unsaturated substrates [Heath96].

Citations: [Mizugaki68, Sharma90, Mohan94]

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Instance reactions of [a (3R)-3-hydroxyacyl-[acyl-carrier protein] → a trans-2-enoyl-[acyl-carrier protein] + H2O] (
i1: (R)-3-hydroxy-cis-vacc-11-enoyl-[acp] → a (2-trans-11-cis)-vaccen-2-enoyl-[acp] + H2O (

i2: a (3R)-3-hydroxystearoyl-[acp] → a trans-octadec-2-enoyl-[acp] + H2O (

i3: a (3R)-3-hydroxylignoceroyl-[acp] → a trans-tetracos-2-enoyl-[acp] + H2O (

i4: a (3R)-3-hydroxycerotoyl-[acp] → a trans-hexacos-2-enoyl-[acp] + H2O (

i5: a (3R)-3-hydroxy-docosapentaenoyl-[acp] = docosapentaenoyl-2-enoyl [acp] + H2O (4.2.1.-)

i6: a (3R)-3-hydroxybutanoyl-[acp] → a crotonyl-[acp] + H2O (

i7: a (3R)-3-hydroxymyristoyl-[acp] → a trans tetradec-2-enoyl-[acp] + H2O (

i8: a (3R)-3-hydroxyoctanoyl-[acp] → a trans oct-2-enoyl-[acp] + H2O (

i9: a (3R)-3-hydroxyarachidoyl-[acp] → a trans-eicos-2-enoyl-[acp] + H2O (

i10: a (3R)-3-hydroxydecanoyl-[acp] → a (2E)-dec-2-enoyl-[acp] + H2O (

i11: a (3R)-3-hydroxypetroselinoyl-[acp] → a (2E,6Z)-octadeca-2,6-dienoyl-[acp] + H2O (4.2.1.-)

i12: a (3R)-3-hydroxyhexanoyl-[acp] → a trans hex-2-enoyl-[acp] + H2O (

i13: a (3R)-3-hydroxybehenoyl-[acp] → a trans-docos-2-enoyl-[acp] + H2O (

i14: a (3R)-3-hydroxypalmitoyl-[acp] → a trans hexadecenoyl-[acp] + H2O (

Relationship Links: BRENDA:EC: , ENZYME:EC: , IUBMB-ExplorEnz:EC:


Heath96: Heath RJ, Rock CO (1996). "Roles of the FabA and FabZ beta-hydroxyacyl-acyl carrier protein dehydratases in Escherichia coli fatty acid biosynthesis." J Biol Chem 1996;271(44);27795-801. PMID: 8910376

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Mizugaki68: Mizugaki M, Swindell AC, Wakil SJ (1968). "Intermediate- and long-chain beta-hydroxyacyl-ACP dehydrases from E. coli fatty acid synthetase." Biochem Biophys Res Commun 33(3);520-7. PMID: 4881058

Mohan94: Mohan S, Kelly TM, Eveland SS, Raetz CR, Anderson MS (1994). "An Escherichia coli gene (FabZ) encoding (3R)-hydroxymyristoyl acyl carrier protein dehydrase. Relation to fabA and suppression of mutations in lipid A biosynthesis." J Biol Chem 1994;269(52);32896-903. PMID: 7806516

Sharma90: Sharma A, Henderson BS, Schwab JM, Smith JL (1990). "Crystallization and preliminary X-ray analysis of beta-hydroxydecanoyl thiol ester dehydrase from Escherichia coli." J Biol Chem 1990;265(9);5110-2. PMID: 2180957

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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