 To complete the general phenylpropanoid pathway, 4-coumarate CoA ligase (4CL) substitutes coenzyme A (CoA) at the carboxy group of "p"-coumarate.Entering the flavone synthesis pathway, the type III polyketide synthase enzyme chalcone synthase (CHS) uses consecutive condensations of three equivalents of malonyl CoA followed by aromatization to convert "p"-coumaroyl-CoA to chalcone.Chalcone isomerase (CHI) then isomerizes the product to close the pyrone ring to make naringenin.