2.3.1.208 evolution biphenyl synthase is a type III polyketide synthase 721091 2.3.1.208 evolution the enzyme belongs to the type III PKS superfamily of enzymes. In a phylogenetic tree, BIS and benzophenone synthase, BPS EC 2.3.1.151, group together closely, indicating that they arise from a relatively recent functional diversification of a common ancestral gene 706131 2.3.1.208 additional information the isozyme contains the Cys-His-Asn catalytic triad conserved in type III PKSs 706258 2.3.1.208 physiological function BIS3 appears to catalyze the formation of phytoalexins in the transition zone, while BIS2 does not 721091 2.3.1.208 physiological function elicitor-treated cell cultures of Sorbus aucuparia form 4-hydroxycoumarin when fed with the N-acetylcysteamine thioester of salicylic acid (salicyl-NAC) 706258 2.3.1.208 physiological function when incubated with 2-hydroxybenzoyl (salicyl)-CoA, BIS catalyzes a single decarboxylative condensation with malonyl-CoA to form 4-hydroxycoumarin, also elicitor-treated cell cultures of Sorbus aucuparia form 4-hydroxycoumarin when fed with the N-acetylcysteamine thioester of salicylic acid (salicyl-NAC). BIS is the key enzyme of biphenyl metabolism biphenyls and the related dibenzofurans are the phytoalexins of the Maloideae. Two molecules of 4-hydroxycoumarin spontaneously combine with formaldehyde to give dicoumarol, which is well-known for its blood anticoagulant activity and is the forerunner of medicinal anticoagulants 706131