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Escherichia coli K-12 substr. MG1655 Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical ReactionsProtein-Modification Reactions
Reactions Classified By SubstrateMacromolecule ReactionsProtein-ReactionsProtein-Modification Reactions

EC Number:

Enzymes and Genes:
KASIInferred from experiment: fabB

In Pathway: 8-amino-7-oxononanoate biosynthesis I

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

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Enzyme Commission Primary Name: β-ketoacyl-[acyl-carrier-protein] synthase I

Enzyme Commission Synonyms: β-ketoacyl-ACP synthase I, β-ketoacyl synthetase, β-ketoacyl-ACP synthetase, β-ketoacyl-acyl carrier protein synthetase, β-ketoacyl-[acyl carrier protein] synthase, β-ketoacylsynthase, condensing enzyme, 3-ketoacyl-acyl carrier protein synthase, fatty acid condensing enzyme, acyl-malonyl(acyl-carrier-protein)-condensing enzyme, acyl-malonyl acyl carrier protein-condensing enzyme, β-ketoacyl acyl carrier protein synthase, 3-oxoacyl-[acyl-carrier-protein] synthase, 3-oxoacyl:ACP synthase I, KASI, KAS I, FabF1, FabB, acyl-[acyl-carrier-protein]:malonyl-[acyl-carrier-protein] C-acyltransferase (decarboxylating)

Enzyme Commission Summary:
This enzyme is responsible for the chain-elongation step of dissociated (type II) fatty-acid biosynthesis, i.e. the addition of two C atoms to the fatty-acid chain. Escherichia coli mutants that lack this enzyme are deficient in unsaturated fatty acids. The enzyme can use fatty acyl thioesters of ACP (C2 to C16) as substrates, as well as fatty acyl thioesters of Co-A (C4 to C16) [DAgnolo75]. The substrate specificity is very similar to that of EC, β-ketoacyl-ACP synthase II, with the exception that the latter enzyme is far more active with palmitoleoyl-ACP (C16Δ9) as substrate, allowing the organism to regulate its fatty-acid composition with changes in temperature [DAgnolo75, Garwin80].

Citations: [Prescott72, Toomey66a, Wang04a, Cronan96, Alberts69]

Gene-Reaction Schematic

Gene-Reaction Schematic

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

Created 04-Jun-2010 by Caspi R, SRI International


Alberts69: Alberts AW, Majerus PW, Vagelos PR (1969). "Acetyl-CoA acyl carrier protein transacylase." Methods Enzymol. 14 5053.

Cronan96: Cronan JE Jr., Rock CO (1996). "Biosynthesis of membrane lipids." In: Neidhardt, F.C. (Ed.), Escherichia coli and Salmonella: Cellular and Molecular Biology, 2nd edn, vol. 1, ASM Press, Washington, DC, pp. 612-636.

DAgnolo75: D'Agnolo G, Rosenfeld IS, Vagelos PR (1975). "Multiple forms of beta-ketoacyl-acyl carrier protein synthetase in Escherichia coli." J Biol Chem 250(14);5289-94. PMID: 237914

Garwin80: Garwin JL, Klages AL, Cronan JE (1980). "Structural, enzymatic, and genetic studies of beta-ketoacyl-acyl carrier protein synthases I and II of Escherichia coli." J Biol Chem 1980;255(24);11949-56. PMID: 7002930

Prescott72: Prescott DJ, Vagelos PR (1972). "Acyl carrier protein." Adv Enzymol Relat Areas Mol Biol 36;269-311. PMID: 4561013

Toomey66a: Toomey RE, Wakil SJ (1966). "Studies on the mechanism of fatty acid synthesis. XVI. Preparation and general properties of acyl-malonyl acyl carrier protein-condensing enzyme from Escherichia coli." J Biol Chem 241(5);1159-65. PMID: 5327099

Wang04a: Wang H, Cronan JE (2004). "Functional replacement of the FabA and FabB proteins of Escherichia coli fatty acid synthesis by Enterococcus faecalis FabZ and FabF homologues." J Biol Chem 279(33);34489-95. PMID: 15194690

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by Pathway Tools version 19.5 (software by SRI International) on Wed Jan 2, 2002, biocyc12.