IUBMB Enzyme Nomenclature


Accepted name: phloroglucinol synthase

Reaction: 3 malonyl-CoA = phloroglucinol + 3 CO2 + 3 CoA

For diagram of reaction click here.

Glossary: phloroglucinol = 1,3,5-trihydroxybenzene

Other name(s): phlD (gene name)

Systematic name: malonyl-CoA:malonyl-CoA malonyltransferase (decarboxylating, phloroglucinol-forming)

Comments: The enzyme, characterized from the bacterium Pseudomonas protegens Pf-5, is a type III polyketide synthase. The mechanism involves the cyclization of an activated 3,5-dioxoheptanedioate intermediate. The enzyme exhibits broad substrate specificity, and can accept C4-C12 aliphatic acyl-CoAs and phenylacetyl-CoA as the starter molecules, forming 6-(polyoxoalkylated)-α-pyrones by sequential condensation with malonyl-CoA.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Achkar, J., Xian, M., Zhao, H. and Frost, J.W. Biosynthesis of phloroglucinol. J. Am. Chem. Soc. 127 (2005) 5332-5333.

2. Zha, W., Rubin-Pitel, S.B. and Zhao, H. Characterization of the substrate specificity of PhlD, a type III polyketide synthase from Pseudomonas fluorescens. J. Biol. Chem. 281 (2006) 32036-32047. [PMID: 16931521]

[EC created 2016]

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