Beta-ketoacyl-ACP synthase
| 3-oxoacyl-ACP synthase, mitochondrial | |||||||
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| Identifiers | |||||||
| Symbol | OXSM | ||||||
| NCBI gene | 54995 | ||||||
| HGNC | 26063 | ||||||
| OMIM | 610324 | ||||||
| RefSeq | NM_017897 | ||||||
| UniProt | Q9NWU1 | ||||||
| Other data | |||||||
| EC number | 2.3.1.41 | ||||||
| Locus | Chr. 3 p24.2 | ||||||
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| Beta-ketoacyl synthase, N-terminal domain | |||||||||
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the crystal structure of beta-ketoacyl-[acyl carrier protein] synthase ii from streptococcus pneumoniae, triclinic form | |||||||||
| Identifiers | |||||||||
| Symbol | ketoacyl-synt | ||||||||
| Pfam | PF00109 | ||||||||
| Pfam clan | CL0046 | ||||||||
| InterPro | IPR014030 | ||||||||
| PROSITE | PDOC00529 | ||||||||
| SCOP2 | 1kas / SCOPe / SUPFAM | ||||||||
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| Beta-ketoacyl synthase, C-terminal domain | |||||||||
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arabidopsis thaliana mitochondrial beta-ketoacyl acp synthase hexanoic acid complex | |||||||||
| Identifiers | |||||||||
| Symbol | Ketoacyl-synt_C | ||||||||
| Pfam | PF02801 | ||||||||
| Pfam clan | CL0046 | ||||||||
| InterPro | IPR014031 | ||||||||
| PROSITE | PDOC00529 | ||||||||
| SCOP2 | 1kas / SCOPe / SUPFAM | ||||||||
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In molecular biology, Beta-ketoacyl-ACP synthase EC 2.3.1.41, is an enzyme involved in fatty acid synthesis. It typically uses malonyl-CoA as a carbon source to elongate ACP-bound acyl species, resulting in the formation of ACP-bound β-ketoacyl species such as acetoacetyl-ACP.
Beta-ketoacyl-ACP synthase is a highly conserved enzyme that is found in almost all life on earth as a domain in fatty acid synthase (FAS). FAS exists in two types, aptly named type I and II. In animals, fungi, and lower eukaryotes, Beta-ketoacyl-ACP synthases make up one of the catalytic domains of larger multifunctional proteins (Type I), whereas in most prokaryotes as well as in plastids and mitochondria, Beta-ketoacyl-ACP synthases are separate protein chains that usually form dimers (Type II). Beta-ketoacyl-ACP synthase III, perhaps the most well known of this family of enzymes, catalyzes a Claisen condensation between acetyl CoA and malonyl ACP. The image below reveals how CoA fits in the active site as a substrate of synthase III.
Beta-ketoacyl-ACP synthases I and II only catalyze acyl-ACP reactions with malonyl ACP. Synthases I and II are capable of producing long-chain acyl-ACPs. Both are efficient up to acyl-ACPs with a 14 carbon chain, at which point synthase II is the more efficient choice for further carbon additions. Type I FAS catalyzes all the reactions necessary to create palmitic acid, which is a necessary function in animals for metabolic processes, one of which includes the formation of sphingosines.
Beta-ketoacyl-ACP synthase is found as a component of a number of enzymatic systems, including fatty acid synthetase (FAS); the multi-functional 6-methysalicylic acid synthase (MSAS) from Penicillium patulum, 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.