MetaCyc Pathway: steroidal glycoalkaloid biosynthesis
Inferred from experiment

Pathway diagram: steroidal glycoalkaloid biosynthesis

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: solanine/chaconine biosynthesis, α-solanine/α-chaconine biosynthesis, SGA biosynthesis

Superclasses: BiosynthesisSecondary Metabolites BiosynthesisNitrogen-Containing Secondary Compounds BiosynthesisAlkaloids Biosynthesis

Some taxa known to possess this pathway include : Solanum tuberosum

Expected Taxonomic Range: Solanaceae

The potato steroidal glycoalkaloids (SGA) are toxic secondary metabolites found in potatoes Solanum tuberosum and other Solanaceous members like tomato and eggplant [McCue07]. They give a bitter taste and their total content should not exceed 20mg/100g fresh weight. The two major SGA's in cultivated potato are α-solanine and α-chaconine [Krits07].

Tuber phelloderm or the layers directly below the tuber skin is the main SGA-producing tissue in potato. Symptoms of SGA poisoning include gastrointestinal disorders, hallucinations, partial paralysis, convulsions, coma and death [Krits07]. At the cellular level they exhibit strong lytic properties and inhibit acetylcholine-esterase activty.

Cooking does not destroy the SGA's and varieties that contain low levels of SGA are bred. The biosynthetic pathway has not been completely worked out and possible positive roles these compounds may play in antifungal and wounding response are being studied. Wounding in potato activates the sterol and SGA synthesis [Krits07].

Created 08-Oct-2007 by Pujar A, Cornell University
Reviewed 14-Jun-2012 by Foerster H, Boyce Thompson Institute


Krits07: Krits P, Fogelman E, Ginzberg I (2007). "Potato steroidal glycoalkaloid levels and the expression of key isoprenoid metabolic genes." Planta NIL. PMID: 17701426

McCue06: McCue KF, Allen PV, Shepherd LV, Blake A, Whitworth J, Maccree MM, Rockhold DR, Stewart D, Davies HV, Belknap WR (2006). "The primary in vivo steroidal alkaloid glucosyltransferase from potato." Phytochemistry 67(15);1590-7. PMID: 16298403

McCue07: McCue KF, Allen PV, Shepherd LV, Blake A, Maccree MM, Rockhold DR, Novy RG, Stewart D, Davies HV, Belknap WR (2007). "Potato glycosterol rhamnosyltransferase, the terminal step in triose side-chain biosynthesis." Phytochemistry 68(3);327-34. PMID: 17157337

Moehs97: Moehs CP, Allen PV, Friedman M, Belknap WR (1997). "Cloning and expression of solanidine UDP-glucose glucosyltransferase from potato." Plant J 11(2);227-36. PMID: 9076990

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

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

Lazarowski03: Lazarowski ER, Shea DA, Boucher RC, Harden TK (2003). "Release of cellular UDP-glucose as a potential extracellular signaling molecule." Mol Pharmacol 63(5);1190-7. PMID: 12695547

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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
Page generated by Pathway Tools version 19.5 (software by SRI International) on Thu Jan 3, 2002, biocyc12.