IUBMB Enzyme Nomenclature


Accepted name: phloroisovalerophenone synthase

Reaction: (1) isovaleryl-CoA + 3 malonyl-CoA = 4 CoA + 3 CO2 + phlorisovalerophenone

(2) isobutyryl-CoA+ 3 malonyl-CoA = 4 CoA + 3 CO2 + phlorisobutyrophenone

For diagram of reaction click here.

Other name(s): valerophenone synthase; 3-methyl-1-(trihydroxyphenyl)butan-1-one synthase

Systematic name: isovaleryl-CoA:malonyl-CoA acyltransferase

Comments: Closely related to EC, naringenin-chalcone synthase. The product, 3-methyl-1-(2,4,6-trihydroxyphenyl)butan-1-one, is phloroisovalerophenone. Also acts on isobutyryl-CoA as substrate to give phlorisobutyrophenone. The products are intermediates in the biosynthesis of the bitter (α) acids in hops (Humulus lupulus).

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


1. Fung, S.Y., Zuurbier, K.W.M., Paniego, N.B., Scheffer, J.J.C. and Verpoorte, R. Enzymes from the biosynthesis of hop α and β acids. Proc. 26th Congr. Eur. Brew. Conv. (1997) 215-221.

2. Zuurbier, K.W.M., Leser, J., Berger, T., Hofte, A.J.P., Schroder, G., Verpoorte, R. and Schroder, J. 4-Hydroxy-2-pyrone formation by chalcone and stilbene synthase with nonphysiological substrates. Phytochemistry 49 (1998) 1945-1951.

3. Song, C., Ring, L., Hoffmann, T., Huang, F.C., Slovin, J. and Schwab, W. Acylphloroglucinol biosynthesis in strawberry fruit. Plant Physiol. 169 (2015) 1656–1670.[PMID: 26169681]

[EC created 2000]

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