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 126.96.36.199, 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]