long-chain-alcohol O-fatty-acyltransferase | |||||||||
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Identifiers | |||||||||
EC no. | 2.3.1.75 | ||||||||
CAS no. | 64060-40-8 | ||||||||
Databases | |||||||||
IntEnz | IntEnz view | ||||||||
BRENDA | BRENDA entry | ||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
Gene Ontology | AmiGO / QuickGO | ||||||||
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In enzymology, a long-chain-alcohol O-fatty-acyltransferase (EC 2.3.1.75) is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are acyl-CoA and long-chain alcohol, whereas its two products are CoA and long-chain ester.
This enzyme belongs to the family of transferases, specifically those acyltransferases transferring groups other than aminoacyl groups. The systematic name of this enzyme class is acyl-CoA:long-chain-alcohol O-acyltransferase. Other names in common use include wax synthase, and wax-ester synthase. In general, wax syntheses naturally accept acyl groups with carbon chain lengths of C16 or C18 and linear alcohols with carbon chain lengths ranging from C12 to C20. [1]
There are three unrelated families of wax syntheses found in many organisms including bacteria, higher plants, and animals [2] in two known distinct forms: either just as a wax synthase enzyme, which is found predominantly in eukaryotes, or as an enzyme with dual wax synthase and acyl CoA:diacylglycerol acyltransferase function, which is often the final enzyme in the biosynthetic pathway responsible for wax ester production from fatty alcohols and fatty acyl-CoAs and is found predominantly in prokaryotes. [3]
There are frequent reports of wax esters biosynthesis in bacteria of the Acinetobacter genus. In particular, it has been shown that the Acinetobacter calcoaceticus ADP1 strain synthesizes wax esters through a bifunctional wax ester synthase/acyl-CoA: diacylglycerol acyltransferase (WS/DGAT) and that this complex can be functionally expressed in different bacterial hosts, suggesting the potential for potential microbial production of cheap jojoba-like wax esters. [4] Furthermore, this was the first instance of bacterial WS/DGAT discovered. [3] Finally, Acinetobacter has been considered as an alternative source for jojoba-like wax ester production, but is limited by the fact that its wax ester content never exceeds 14% of the cell's dry weight. [5]
Scientists have identified at least 14 genes in the Rhodococcus jostii RHA1 genome that encode putative wax ester synthase/acyl-CoA:diacylglycerol acyltransferase enzymes (WS/DGAT) with lengths ranging from 430 to 497 amino acid residues except for atf121 product, which was composed of 301 amino acid residues. [6] [7]
Other bacteria that have been shown to produce wax esters through homologs for the WS/DGAT gene include Psychrobacter arcticus 273-4 and P. Cryohalolentis K5, with only one a single copy of the WS/DGAT gene, M. aquaeolei VT8, with 4 homologs for WS/DGAT and A. Baylyi, with a mixture of wax esters even though it only has one WS/DGAT coding gene. [4] "M. tuberculosis" has also been shown to contain 15 atf genes encoding WS/DGATs. [8] Several of these bacterial WS/DGAT enzymes have a broad substrate range despite naturally producing a small range of wax esters. [9] [10] [11]
Scientists have also identified, characterized, and shown the WSD1 gene in Arabidopsis thaliana to encode a bifunctional wax ester synthase/diacylglycerol acyltransferase enzyme that is embedded in the ER membrane, in which the wax synthase portion is critical to wax ester synthesis using long-chain and very-long-chain primary alcohols with C fatty acids. [12]
Although the first wax synthase in plants was identified in the jojoba plant, the jojoba wax synthase could not be functionally expressed in microorganisms like E. coli and S. cerevisiae . [13]
The enzyme products of genes AdWS4, TaWS4, GgWS1, GgWS2, GgWS4, and GgDGAT1 sequences have been shown to catalyze wax ester syntheses in several bird species. [14]
Scientists have discovered cDNA encoding wax synthase in the preputial gland of mice. [15] Furthermore, it has been shown that the wax synthase gene is located on the X chromosome, the expression of which lead to the formation of wax monoesters from straight chain, saturated, unsaturated, and polyunsaturated fatty alcohols and acids and that the formation of wax esters in mammals involves a two step biosynthetic pathway involving fatty acyl-CoA reductase and wax synthase enzymes. [15]
The enzymes produced by X-linked genes AWAT1 and AWAT2 have been shown to esterify long chain alcohols to produce wax esters and is most predominantly expressed in skin. [16] Both enzymes have dissimilar substrate specificities: AWAT1 prefers decyl alcohol (C10) and AWAT2 prefers C16 and C18 alcohols while using oleoyl-CoA as the acyl donor. However, when using acetyl alcohol as the acyl acceptor, AWAT1 prefers saturated acyl groups, while AWAT2 shows activity with all four acyl-CoAs and performs two times better with unsaturated acyl-CoAs than with saturated ones. [16] Along with the murine wax ester synthase, AWAT1 and AWAT2 are likely the most significant contributors in wax ester production in mammals. [16]
While the function of the molecule has been studied, its structure has yet to be identified.
There is a large demand for large-scale production of cheap jojoba-like wax esters since they have multiple commercial uses. [4] Scientists have found a way to achieve substantial biosynthesis and accumulation of neutral lipids in "E. coli", allowing for the possibilities of economic biotechnological production of cheap jojoba oil equivalents, the use of which was previously limited by its high price resulting in its restriction to medical and cosmetic applications. [17]
In addition, the knowledge gathered so far on the substrate specificity of different forms of wax synthase allows for scientists to explore the use of yeast cells, in particular Saccharomyces cerevisiae , in the production of biodiesel fuels. "S. Cerevisiae" is a well-documented industrial microorganism and is easy to cultivate, manipulate genetically, quick growth, and fatty acid metabolism, making it an ideal candidate for the expression of wax esters. [1] S. Cerevisiae is further suitable as for this task as they produce the necessary reactants for wax syntheses to create wax esters. [1] Scientists have investigated the possibility of expressing different wax synthase genes, including those of A. baylyi ADP1, M. hydrocarbonoclasticus DSM 8798, R. opacus PD630, M. musculus C57BL/6 and P. arcticus 273-4, in S. cerevisiae , and found that that of Marinobacter hydrocarbonoclasticus DSM 8798 was the most effective since it showed highest relative preference for ethanol, thus allowing for the production of biodiesel fuels, in part taking advantage of the enzyme's promiscuous nature. [1]
Malonyl-CoA is a coenzyme A derivative of malonic acid.
Polyketide synthases (PKSs) are a family of multi-domain enzymes or enzyme complexes that produce polyketides, a large class of secondary metabolites, in bacteria, fungi, plants, and a few animal lineages. The biosyntheses of polyketides share striking similarities with fatty acid biosynthesis.
Acyl-CoA is a group of coenzymes that metabolize fatty acids. Acyl-CoA's are susceptible to beta oxidation, forming, ultimately, acetyl-CoA. The acetyl-CoA enters the citric acid cycle, eventually forming several equivalents of ATP. In this way, fats are converted to ATP, the universal biochemical energy carrier.
The long chain fatty acyl-CoA ligase is an enzyme of the ligase family that activates the oxidation of complex fatty acids. Long chain fatty acyl-CoA synthetase catalyzes the formation of fatty acyl-CoA by a two-step process proceeding through an adenylated intermediate. The enzyme catalyzes the following reaction,
Doxorubicin (DXR) is a 14-hydroxylated version of daunorubicin, the immediate precursor of DXR in its biosynthetic pathway. Daunorubicin is more abundantly found as a natural product because it is produced by a number of different wild type strains of streptomyces. In contrast, only one known non-wild type species, streptomyces peucetius subspecies caesius ATCC 27952, was initially found to be capable of producing the more widely used doxorubicin. This strain was created by Arcamone et al. in 1969 by mutating a strain producing daunorubicin, but not DXR, at least in detectable quantities. Subsequently, Hutchinson's group showed that under special environmental conditions, or by the introduction of genetic modifications, other strains of streptomyces can produce doxorubicin. His group has also cloned many of the genes required for DXR production, although not all of them have been fully characterized. In 1996, Strohl's group discovered, isolated and characterized dox A, the gene encoding the enzyme that converts daunorubicin into DXR. By 1999, they produced recombinant Dox A, a Cytochrome P450 oxidase, and found that it catalyzes multiple steps in DXR biosynthesis, including steps leading to daunorubicin. This was significant because it became clear that all daunorubicin producing strains have the necessary genes to produce DXR, the much more therapeutically important of the two. Hutchinson's group went on to develop methods to improve the yield of DXR, from the fermentation process used in its commercial production, not only by introducing Dox A encoding plasmids, but also by introducing mutations to deactivate enzymes that shunt DXR precursors to less useful products, for example baumycin-like glycosides. Some triple mutants, that also over-expressed Dox A, were able to double the yield of DXR. This is of more than academic interest because at that time DXR cost about $1.37 million per kg and current production in 1999 was 225 kg per annum. More efficient production techniques have brought the price down to $1.1 million per kg for the non-liposomal formulation. Although DXR can be produced semi-synthetically from daunorubicin, the process involves electrophilic bromination and multiple steps and the yield is poor. Since daunorubicin is produced by fermentation, it would be ideal if the bacteria could complete DXR synthesis more effectively.
Diglyceride acyltransferase, DGAT, catalyzes the formation of triglycerides (triacylglycerols) from diacylglycerol and acyl-CoA. The reaction catalyzed by DGAT is considered the terminal and only committed step in the acyl-CoA depedent triglyceride synthesis, univerally important in animal, plants, and microorganisms. The conversion is essential for intestinal absorption and adipose tissue formation in mamalian. DGAT1 are homologous to other membrane-bound O-acyltransferases, but other DGATs are not.
In enzymology, a [acyl-carrier-protein] S-acetyltransferase is an enzyme that catalyzes the reversible chemical reaction
In enzymology, a [acyl-carrier-protein] S-malonyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a beta-ketoacyl-acyl-carrier-protein synthase II (EC 2.3.1.179) is an enzyme that catalyzes the chemical reaction
In enzymology, an erythronolide synthase is an enzyme that catalyzes the chemical reaction
In enzymology, sphingosine N-acyltransferases (ceramide synthases (CerS), EC 2.3.1.24) are enzymes that catalyze the chemical reaction of synthesis of ceramide:
Sterol O-acyltransferase is an intracellular protein located in the endoplasmic reticulum that forms cholesteryl esters from cholesterol.
Sterol O-acyltransferase 2, also known as SOAT2, is an enzyme that in humans is encoded by the SOAT2 gene.
Fatty acyl-CoA reductase 1 is an enzyme that in humans is encoded by the FAR1 gene.
2-acyl-sn-glycero-3-phosphocholines are a class of phospholipids that are intermediates in the metabolism of lipids. Because they result from the hydrolysis of an acyl group from the sn-1 position of phosphatidylcholine, they are also called 1-lysophosphatidylcholine. The synthesis of phosphatidylcholines with specific fatty acids occurs through the synthesis of 1-lysoPC. The formation of various other lipids generates 1-lysoPC as a by-product.
Very-long-chain 3-oxoacyl-CoA synthase (EC 2.3.1.199, very-long-chain 3-ketoacyl-CoA synthase, very-long-chain beta-ketoacyl-CoA synthase, condensing enzyme, CUT1 (gene), CERS6 (gene), FAE1 (gene), KCS (gene), ELO (gene)) is an enzyme with systematic name malonyl-CoA:very-long-chain acyl-CoA malonyltransferase (decarboxylating and thioester-hydrolysing). This enzyme catalyses the following chemical reaction
Ketoacyl synthases (KSs) catalyze the condensation reaction of acyl-CoA or acyl-acyl ACP with malonyl-CoA to form 3-ketoacyl-CoA or with malonyl-ACP to form 3-ketoacyl-ACP. This reaction is a key step in the fatty acid synthesis cycle, as the resulting acyl chain is two carbon atoms longer than before. KSs exist as individual enzymes, as they do in type II fatty acid synthesis and type II polyketide synthesis, or as domains in large multidomain enzymes, such as type I fatty acid synthases (FASs) and polyketide synthases (PKSs). KSs are divided into five families: KS1, KS2, KS3, KS4, and KS5.
Diacylglycerol O-acyltransferase 1 is an enzyme that in humans is encoded by the DGAT1 gene.
Diacylglycerol O-acyltransferase 2 (DGAT2) is a protein that in humans is encoded by the DGAT2 gene.
An oleaginous microorganism is a type of microbe that accumulates lipid as a normal part of its metabolism. Oleaginous microbes may accumulate an array of different lipid compounds, including polyhydroxyalkanoates, triacylglycerols, and wax esters. Various microorganisms, including bacteria, fungi, and yeast, are known to accumulate lipids. These organisms are often researched for their potential use in producing fuels from waste products.