Beta-ketoacyl-ACP synthase

In molecular biology, Beta-ketoacyl-ACP synthase EC 2.3.1.41, is an enzyme involved in fatty acid synthesis. It results in the formation of acetoacetyl ACP.

It is the enzyme that catalyses the condensation of malonyl-ACP with the growing fatty acid chain.^[1] It is found as a component of a number of enzymatic systems, including fatty acid synthetase (FAS), which catalyses the formation of long-chain fatty acids from acetyl-CoA, malonyl-CoA and NADPH; the multi-functional 6-methysalicylic acid synthase (MSAS) from Penicillium patulum,^[2] which is involved in the biosynthesis of a polyketide antibiotic; polyketide antibiotic synthase enzyme systems; Emericella nidulans multifunctional protein Wa, which is involved in the biosynthesis of conidial green pigment; Rhizobium nodulation protein nodE, which probably acts as a beta-ketoacyl synthase in the synthesis of the nodulation Nod factor fatty acyl chain; and yeast mitochondrial protein CEM1. The condensation reaction is a two-step process: first the acyl component of an activated acyl primer is transferred to a cysteine residue of the enzyme and is then condensed with an activated malonyl donor with the concomitant release of carbon dioxide.

Beta-ketoacyl synthase contains two protein domains. The active site is located between the N- and C-terminal domains. The N-terminal domain contains most of the structures involved in dimer formation and also the active site cysteine. Residues from both domains contribute to substrate binding and catalysis^[3]

External links

beta Ketoacyl ACP Synthase at the US National Library of Medicine Medical Subject Headings (MeSH)

References

↑ Kauppinen S, Siggaard-Andersen M, von Wettstein-Knowles P (1988). "beta-Ketoacyl-ACP synthase I of Escherichia coli: nucleotide sequence of the fabB gene and identification of the cerulenin binding residue". Carlsberg Res. Commun. 53 (6): 357–70. doi:10.1007/bf02983311. PMID 3076376.
↑ Beck J, Ripka S, Siegner A, Schiltz E, Schweizer E (September 1990). "The multifunctional 6-methylsalicylic acid synthase gene of Penicillium patulum. Its gene structure relative to that of other polyketide synthases". Eur. J. Biochem. 192 (2): 487–98. doi:10.1111/j.1432-1033.1990.tb19252.x. PMID 2209605.
↑ Huang W, Jia J, Edwards P, Dehesh K, Schneider G, Lindqvist Y (1998). "Crystal structure of beta-ketoacyl-acyl carrier protein synthase II from E.coli reveals the molecular architecture of condensing enzymes.". EMBO J 17 (5): 1183–91. doi:10.1093/emboj/17.5.1183. PMC 1170466. PMID 9482715.

This article incorporates text from the public domain Pfam and InterPro IPR014030

This article incorporates text from the public domain Pfam and InterPro IPR014031

Transferases: acyltransferases (EC 2.3)

2.3.1: other than amino-acyl groups	acetyltransferases: Acetyl-Coenzyme A acetyltransferase N-Acetylglutamate synthase Choline acetyltransferase Dihydrolipoyl transacetylase Acetyl-CoA C-acyltransferase Beta-galactoside transacetylase Chloramphenicol acetyltransferase N-acetyltransferase Serotonin N-acetyl transferase HGSNAT ARD1A Histone acetyltransferase P300/CBP NAT2 palmitoyltransferases: Carnitine O-palmitoyltransferase CPT1 CPT2 Serine C-palmitoyltransferase SPTLC1 SPTLC2 other: Acyltransferase like 2 Aminolevulinic acid synthase Beta-ketoacyl-ACP synthase Glyceronephosphate O-acyltransferase Lecithin—cholesterol acyltransferase Glycerol-3-phosphate O-acyltransferase 1-acylglycerol-3-phosphate O-acyltransferase 2-acylglycerol-3-phosphate O-acyltransferase ABHD5

2.3.2: Aminoacyltransferases	Gamma-glutamyl transpeptidase Peptidyl transferase Transglutaminase Tissue transglutaminase Keratinocyte transglutaminase Factor XIII

2.3.3: converted into alkyl on transfer	Citrate synthase ATP citrate lyase HMG-CoA synthase Malate synthase

Metabolism: lipid metabolism / fatty acid metabolism, triglyceride and fatty acid enzymes

Synthesis

Malonyl-CoA synthesis	ATP citrate lyase Acetyl-CoA carboxylase

Fatty acid synthesis/ Fatty acid synthase	Beta-ketoacyl-ACP synthase Β-Ketoacyl ACP reductase 3-Hydroxyacyl ACP dehydrase Enoyl ACP reductase

Fatty acid desaturases	Stearoyl-CoA desaturase-1

Triacyl glycerol	Glycerol-3-phosphate dehydrogenase Thiokinase

Degradation

Acyl transport

Beta oxidation

General	Acyl CoA dehydrogenase (ACADL ACADM ACADS ACADVL ACADSB) Enoyl-CoA hydratase MTP: HADH HADHA HADHB Acetyl-CoA C-acyltransferase

Unsaturated	Enoyl CoA isomerase 2,4 Dienoyl-CoA reductase

Odd chain	Propionyl-CoA carboxylase

Other	Hydroxyacyl-Coenzyme A dehydrogenase

To acetyl-CoA

Malonyl-CoA decarboxylase

Aldehydes

Long-chain-aldehyde dehydrogenase

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Beta-ketoacyl-ACP synthase

See also

External links

References