MetaCyc Pathway: wax esters biosynthesis I
Inferred from experiment

Pathway diagram: wax esters biosynthesis I

This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Synonyms: jojoba wax biosynthesis, liquid seed wax biosynthesis

Superclasses: BiosynthesisFatty Acid and Lipid Biosynthesis

Some taxa known to possess this pathway include : Simmondsia chinensis

Expected Taxonomic Range: Simmondsia

Seeds of the desert shrub jojoba ( Simmondsia chinensis) contain an unique wax, composed of esters of long-chain fatty acids (18:1, 20:1, 22:1) and long-chain alcohols. It is unique among higher plants in that the seed stores lipids in the form of liquid wax [Lardizabal00].

The waxes are produced in developing embryos during seed formation. The commercial interest in cultivating this plant for industrial and pharmaceutical use of its wax has lead to the identification of the biosynthetic pathways and some genes have been cloned. Transgenic technology has enabled the engineering of these genes into other plants with promising results. Several U.S patents exists for the enzymes of this pathway, given their potential use in industry [Lassner96].

This pathway is carried forward by an alcohol-forming fatty acyl-CoA reductase (FAR) that is part of the integral membrane. This enzyme carries out the reduction of fatty acyl-CoA to a fatty alcohol by a four-electron transfer [Metz00]. NADH or NADPH are used as cofactors, and the reaction proceeds through an aldehyde intermediate that is not released from the active site. These enzymes are distinct from other soluble FAR's that carry out the reduction in a two step electron transfer, the first yields an aldehyde and a second step is involved in the formation of an alcohol.

Jojoba wax synthase shares protein sequence identity with seven Arabidopsis genes, though none have been isolated yet. Co-expression of the enzyme complement of jojoba KCS, FAR and WS in transgenic Arabidopsis plants resulted in the production of large amounts of wax in the seeds [Lassner99]. Wax monoester production in mammals seems to be carried out by enzymes that do not resemble the plant wax synthases described in this pathway (based on the cloning and characterization of wax synthase from mouse preputial glands) [Cheng04a].

Created 15-Apr-2008 by Pujar A, Cornell University


Cheng04a: Cheng JB, Russell DW (2004). "Mammalian wax biosynthesis. II. Expression cloning of wax synthase cDNAs encoding a member of the acyltransferase enzyme family." J Biol Chem 279(36);37798-807. PMID: 15220349

Lardizabal00: Lardizabal KD, Metz JG, Sakamoto T, Hutton WC, Pollard MR, Lassner MW (2000). "Purification of a jojoba embryo wax synthase, cloning of its cDNA, and production of high levels of wax in seeds of transgenic arabidopsis." Plant Physiol 122(3);645-55. PMID: 10712527

Lassner96: Lassner MW, Lardizabal K, Metz JG (1996). "A jojoba beta-Ketoacyl-CoA synthase cDNA complements the canola fatty acid elongation mutation in transgenic plants." Plant Cell 8(2);281-92. PMID: 8742713

Lassner99: Lassner, M.W, Lardizabal, K, Metz, J.G (1999). "producing wax esters in transgenic plants by expression of genes derived from jojoba." Perspectives on new crops and new uses, J.Janick (ed.), ASHS Press, Alexandria, VA.

Metz00: Metz JG, Pollard MR, Anderson L, Hayes TR, Lassner MW (2000). "Purification of a jojoba embryo fatty acyl-coenzyme A reductase and expression of its cDNA in high erucic acid rapeseed." Plant Physiol 2000;122(3);635-44. PMID: 10712526

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Aarts97: Aarts MG, Hodge R, Kalantidis K, Florack D, Wilson ZA, Mulligan BJ, Stiekema WJ, Scott R, Pereira A (1997). "The Arabidopsis MALE STERILITY 2 protein shares similarity with reductases in elongation/condensation complexes." Plant J 12(3);615-23. PMID: 9351246

Cheng04b: Cheng JB, Russell DW (2004). "Mammalian wax biosynthesis. I. Identification of two fatty acyl-Coenzyme A reductases with different substrate specificities and tissue distributions." J Biol Chem 279(36);37789-97. PMID: 15220348

King07: King A, Nam JW, Han J, Hilliard J, Jaworski JG (2007). "Cuticular wax biosynthesis in petunia petals: cloning and characterization of an alcohol-acyltransferase that synthesizes wax-esters." Planta 226(2);381-94. PMID: 17323080

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

Lubert: Lubert Stryer "Biochemistry." ISBN 0-7167-1226-1.

Ozawa96: Ozawa R, Matsumoto S (1996). "Intracellular signal transduction of PBAN action in the silkworm, Bombyx mori: involvement of acyl CoA reductase." Insect Biochem Mol Biol 26(3);259-65. PMID: 8900596

Rubio06: Rubio S, Larson TR, Gonzalez-Guzman M, Alejandro S, Graham IA, Serrano R, Rodriguez PL (2006). "An Arabidopsis mutant impaired in coenzyme A biosynthesis is sugar dependent for seedling establishment." Plant Physiol 140(3);830-43. PMID: 16415216

Uthoff05: Uthoff S, Stoveken T, Weber N, Vosmann K, Klein E, Kalscheuer R, Steinbuchel A (2005). "Thio wax ester biosynthesis utilizing the unspecific bifunctional wax ester synthase/acyl coenzyme A:diacylglycerol acyltransferase of Acinetobacter sp. strain ADP1." Appl Environ Microbiol 71(2);790-6. PMID: 15691932

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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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