| abstract |
A host cell comprising a chalcone synthase (CHS) polypeptide sequence and a 4-coumarate CoA: ligase (4CL) sequence in which one or both are heterologous to the cell. A method of enabling benzalacetone synthase activity of a CHS protein comprising exposing the CHS to a microbial cellular environment, preferably an E. coli cell. The benzalacetone may be reduced by benzalacetone reductase (BAR) in the bacterial cell to make raspberry ketone (pHBD). The host cell may be supplied with a raspberry ketone precursor, preferably benzalacetone or p-coumaric acid. Sequences of raspberry CHS, tobacco 4CL and raspberry BAR genes and polypeptides are described as are vectors comprising CHS and 4CL sequences, preferably in combination with a PAL (phenylalanine ammonia-lyase) gene or a cinnamic acid 4-hydroxylase (C4H) gene. The invention is based on the surprising discovery that chalcone synthase has benzalacetone synthase (BAS) activity. |