MetaCyc Pathway: β-alanine degradation II
Inferred from experiment

Pathway diagram: beta-alanine degradation II

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.

Superclasses: Degradation/Utilization/AssimilationAmino Acids DegradationOther Amino Acids Degradationbeta-Alanine Degradation

Some taxa known to possess this pathway include : Pseudomonas fluorescens

Expected Taxonomic Range: Proteobacteria

β-Alanine is a naturally occurring β-amino acid found in animals, plants [Stinson69], and microorganisms. It differs from L-alanine (an α-amino acid) in the position of the amino group on the β carbon, rather than the α carbon. In the pathway shown here, β-alanine is converted to malonate semialdehyde by transamination of pyruvate to L-alanine, in a pyruvate-dependent reaction. α-Ketoglutarate (2-oxoglutarate) cannot be substituted for pyruvate [Hayaishi61]. Malonate semialdehyde is then converted to acetyl-CoA and CO2 in an oxidative decarboxylation step. Both of the enzymes have been purified and characterized [Hayaishi61] and their reactions have been established as the route of β-alanine degradation in this organism [Hayaishi61]. These authors demonstrated stoichiometric quantities of malonate semialdehyde and L-alanine formed from β-alanine and pyruvate; and acetyl-CoA and CO2 formed from malonate semialdehyde and CoA.

In the malonate-semialdehyde dehydrogenase reaction, the authors noted that this enzyme simultaneously catalyzes the dehydrogenation and decarboxylation of malonate semialdehyde to a thioester CoA derivative. However, their data ruled out acetaldehyde and malonyl-CoA as free intermediates, as well as the participation of a malonyl semialdehyde-CoA intermediate [Hayaishi61]. Therefore, intermediates in this reaction are hypothetical. The formation of CO2 was demonstrated using β-alanine-1-C14. Radioactive CO2 was formed from the carbonyl carbon of malonate semialdehyde [Hayaishi61]. Using the same strain of P. fluorescens, β-alanine degradation was shown to be an inducible pathway when P. fluorescens was grown with β-alanine as a sole carbon and nitrogen source. The two reactions were identified as EC and EC [Hechtman70].

Unlike L-alanine, β-alanine is not incorporated into proteins. In microorganisms and plants, β-alanine is used in the biosynthesis of the vitamin pantothenate which is then used for coenzyme A and acyl carrier protein biosynthesis. Animals lack this pathway and must obtain the vitamin in their diet. In microorganisms, β-alanine is generally synthesized by decarboxylation of L-aspartate [Cronan80].

It should be noted that the strain of P. fluorescens in which this β-alanine degradation pathway was extensively studied [Hayaishi61] has been classified as P. putida by the American Type Culture Collection (ATCC) under deposit number 11250.

A mammalian pathway for β-alanine degradation in rat liver is described in MetaCyc pathway β-alanine degradation I.

Variants: β-alanine degradation I

Relationship Links: KEGG:PART-OF:MAP00410


Cronan80: Cronan JE (1980). "Beta-alanine synthesis in Escherichia coli." J Bacteriol 1980;141(3);1291-7. PMID: 6767707

Hayaishi61: Hayaishi O, NISHIZUKA Y, TATIBANA M, TAKESHITA M, KUNO S (1961). "Enzymatic studies on the metabolism of beta-alanine." J Biol Chem 236;781-90. PMID: 13712439

Hechtman70: Hechtman P, Scriver CR, Middleton RB (1970). "Isolation and properties of a beta-alanine transaminaseless mutant of Pseudomonas fluorescens." J Bacteriol 104(2);851-6. PMID: 5489438

Stinson69: Stinson RA, Spencer MS (1969). "Beta alanine aminotransferase (s) from a plant source." Biochem Biophys Res Commun 34(1);120-7. PMID: 5762452

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

Anderson71: Anderson WA, Magasanik B (1971). "The pathway of myo-inositol degradation in Aerobacter aerogenes. Conversion of 2-deoxy-5-keto-D-gluconic acid to glycolytic intermediates." J Biol Chem 1971;246(18);5662-75. PMID: 4328832

Goodwin89: Goodwin GW, Rougraff PM, Davis EJ, Harris RA (1989). "Purification and characterization of methylmalonate-semialdehyde dehydrogenase from rat liver. Identity to malonate-semialdehyde dehydrogenase." J Biol Chem 264(25);14965-71. PMID: 2768248

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

Otzen14: Otzen C, Bardl B, Jacobsen ID, Nett M, Brock M (2014). "Candida albicans utilizes a modified β-oxidation pathway for the degradation of toxic propionyl-CoA." J Biol Chem 289(12);8151-69. PMID: 24497638

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

StinesChaumeil06: Stines-Chaumeil C, Talfournier F, Branlant G (2006). "Mechanistic characterization of the MSDH (methylmalonate semialdehyde dehydrogenase) from Bacillus subtilis." Biochem J 395(1);107-15. PMID: 16332250

Stinson69a: Stinson R.A., Spencer M.S. "β-Alanine aminotransferase(s) from a plant source." Biochem. Biophys. Res. Commun. (1969) 34(1) : 120-127.

Yonaha83: Yonaha K, Toyama S, Kagamiyama H (1983). "Properties of the bound coenzyme and subunit structure of omega-amino acid:pyruvate aminotransferase." J Biol Chem 258(4);2260-5. PMID: 6822556

Yonaha92: Yonaha K, Nishie M, Aibara S (1992). "The primary structure of omega-amino acid:pyruvate aminotransferase." J Biol Chem 267(18);12506-10. PMID: 1618757

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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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