Type III polyketide synthase involved in the biosynthesis of benzophenones and xanthones. Produces mainly 2,4,6-trihydroxybenzophenone together with minor amounts of tetraketide lactone, triketide lactone and diketide lactone. The preferred substrate is benzoyl-CoA, but can also use acetyl-CoA, phenylacetyl-CoA, hexanoyl-CoA, cinnamoyl-CoA, p-coumaroyl-CoA and salicoyl-CoA. benzoyl-CoA + 2 H(+) + 3 malonyl-CoA = 2,4,6-trihydroxybenzophenone + 3 CO2 + 4 CoA kcat is 2.97 min(-1) with benzoyl-CoA as substrate. kcat is 3.49 min(-1) with malonyl-CoA as substrate. Optimum pH is 6.5-7.0. Optimum temperature is 30 degrees Celsius. Homodimer. Expressed in young fruit pericarp. Belongs to the thiolase-like superfamily. Chalcone/stilbene synthases family.