MetaCyc Reaction:

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

EC Number:,,

Enzymes and Genes:

Arabidopsis thaliana col: 3-oxoacyl-[acyl-carrier-protein] reductase, chloroplasticInferred from experiment: AT1G24360
Escherichia coli K-12 substr. MG1655: 3-oxoacyl-[acyl-carrier-protein] reductase: fabG
Homo sapiens: fatty acid synthase: FASN
Mycobacterium tuberculosis H37Rv: fatty acid synthaseInferred by computational analysis: fas
Pseudomonas aeruginosa: NADPH-dependent β-ketoacyl reductase: rhlG
Saccharomyces cerevisiae: fatty acid synthase, α subunit: FAS2

In Pathway: palmitate biosynthesis I (animals and fungi), palmitate biosynthesis II (bacteria and plants)

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.

Direct generic reaction:
a (3R)-3-hydroxyacyl-[acyl-carrier protein] + NADP+ ← a 3-oxoacyl-[acp] + NADPH + H+ (

Enzyme Commission Primary Name for 3-oxoacyl-[acyl-carrier-protein] reductase

Enzyme Commission Synonyms for β-ketoacyl-[acyl-carrier protein](ACP) reductase, β-ketoacyl acyl carrier protein (ACP) reductase, β-ketoacyl reductase, β-ketoacyl thioester reductase, β-ketoacyl-ACP reductase, β-ketoacyl-acyl carrier protein reductase, 3-ketoacyl acyl carrier protein reductase, NADPH-specific 3-oxoacyl-[acylcarrier protein]reductase, 3-oxoacyl-[ACP]reductase, (3R)-3-hydroxyacyl-[acyl-carrier-protein]:NADP+ oxidoreductase

Enzyme Commission Primary Name for fatty-acid synthase

Enzyme Commission Synonyms for FASN (gene name)

Enzyme Commission Primary Name for fatty-acyl-CoA synthase

Enzyme Commission Synonyms for yeast fatty acid synthase, FAS1 (gene name), FAS2 (gene name)

Standard Gibbs Free Energy (ΔrG in kcal/mol): 20.375793Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary for
Exhibits a marked preference for acyl-carrier-protein derivatives over CoA derivatives as substrates.

Enzyme Commission Summary for
The animal enzyme is a multi-functional protein catalysing the reactions of EC, [acyl-carrier-protein] S-acetyltransferase, EC, [acyl-carrier-protein] S-malonyltransferase, EC, β-ketoacyl-[acyl-carrier-protein] synthase I, EC, 3-oxoacyl-[acyl-carrier-protein] reductase, EC, 3-hydroxyacyl-[acyl-carrier-protein] dehydratase, EC, enoyl-[acyl-carrier-protein] reductase (NADPH, Re-specific) and EC, oleoyl-[acyl-carrier-protein] hydrolase. cf. EC, fatty-acyl-CoA synthase.

Enzyme Commission Summary for
The enzyme from yeasts ( Ascomycota and Basidiomycota) is a multi-functional protein complex composed of two subunits. One subunit catalyses the reactions EC, 3-oxoacyl-[acyl-carrier-protein] reductase and EC, β-ketoacyl-[acyl-carrier-protein] synthase I, while the other subunit catalyses the reactions of EC, [acyl-carrier-protein] S-acetyltransferase, EC, [acyl-carrier-protein] S-malonyltransferase, EC, 3-hydroxyacyl-[acyl-carrier-protein] dehydratase, EC, enoyl-[acyl-carrier-protein] reductase (NADPH, Si-specific) and EC, (R)-3-hydroxyacid-ester dehydrogenase. The enzyme differs from the animal enzyme ( EC in that the enoyl reductase domain requires FMN as a cofactor, and the ultimate product is an acyl-CoA (usually palmitoyl-CoA) instead of a free fatty acid.

Citations: [Prescott72, Shimakata82, Toomey66, Stoops79, Wakil83, Schweizer73, Tehlivets07]

Gene-Reaction Schematic

Gene-Reaction Schematic

Instance reaction of [a (3R)-3-hydroxyacyl-[acyl-carrier protein] + NADP+ ← a 3-oxoacyl-[acp] + NADPH + H+] (
i1: a (3R)-3-hydroxymyristoyl-[acp] + NADP+ ← a 3-oxo-myristoyl-[acp] + NADPH + H+ (



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

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

Schweizer73: Schweizer E, Kniep B, Castorph H, Holzner U (1973). "Pantetheine-free mutants of the yeast fatty-acid-synthetase complex." Eur J Biochem 39(2);353-62. PMID: 4590449

Shimakata82: Shimakata T, Stumpf PK (1982). "Purification and characterizations of beta-Ketoacyl-[acyl-carrier-protein] reductase, beta-hydroxyacyl-[acyl-carrier-protein] dehydrase, and enoyl-[acyl-carrier-protein] reductase from Spinacia oleracea leaves." Arch Biochem Biophys 218(1);77-91. PMID: 6756317

Stoops79: Stoops JK, Ross P, Arslanian MJ, Aune KC, Wakil SJ, Oliver RM (1979). "Physicochemical studies of the rat liver and adipose fatty acid synthetases." J Biol Chem 254(15);7418-26. PMID: 457689

Tehlivets07: Tehlivets O, Scheuringer K, Kohlwein SD (2007). "Fatty acid synthesis and elongation in yeast." Biochim Biophys Acta 1771(3);255-70. PMID: 16950653

Toomey66: Toomey RE, Wakil SJ (1966). "Studies on the mechanism of fatty acid synthesis. XV. Preparation and general properties of beta-ketoacyl acyl carrier protein reductase from Escherichia coli." Biochim Biophys Acta 116(2);189-97. PMID: 4381013

Wakil83: Wakil SJ, Stoops JK, Joshi VC (1983). "Fatty acid synthesis and its regulation." Annu Rev Biochem 52;537-79. PMID: 6137188

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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