Bifunctional polyketide synthase producing both 4-hydroxybenzalacetone and naringenin chalcone. Can use p-coumaryl-CoA and ferulyl-CoA as substrates. Catalyzes the initial key reaction step in the biosynthesis of phenylbutanoids. 4-coumaroyl-CoA + H(+) + H2O + malonyl-CoA = 4-hydroxybenzalacetone + 2 CO2 + 2 CoA 4-coumaroyl-CoA + 2 H(+) + 3 malonyl-CoA = 2',4,4',6'-tetrahydroxychalcone + 3 CO2 + 4 CoA Inhibited by glutathione. Optimum pH is approximately 8.0. Secondary metabolite biosynthesis; flavonoid biosynthesis. Homodimer. Expressed in fruits. Progressively accumulates in fruits when berries are white and full size until complete ripening. By sucrose (at protein level). Belongs to the thiolase-like superfamily. Chalcone/stilbene synthases family.