The BAHD acyltransferases are a super family of enzymes found primarily in plants, algae and bacteria. They are CoA-dependent enzymes that transfer acylated moieties (RC(O)R’) of an acyl-activated CoA thioester donor to an acceptor molecule (D’Auria, 2006). Phylogenetic analysis using full-length amino acid sequences of functionally characterized BAHD enzymes by D’Auria (2006) and Stewart et al. (2005) shows that they form five distinctive clades that correlate to general function. BAHDs typically have low substrate selectivity, and can use a variety of CoA thioester and alcohol co-substrates. The acronym BAHD refers to the first letter of the first four enzymes that were discovered to belong to this family.
In plants, BAHD acyltransferases are often involved in the production of phenolic secondary metabolites, for example in Poplar (Populus trichocarpa) at least two BAHD acyltransferases are required for the production of potent defence/anti-herbivory compounds known as the salicinoid phenolic glycosides (Chedgy et al., 2015). These are benzoyl-CoA:benzyl alcohol O-benzoyltransferase (PtBEBT) that produces benzyl benzoate from benzoyl-CoA and benzyl alcohol (Chedgy et al., 2015), and benzoyl-CoA:salicyl alcohol O-benzoyltransferase (PtSABT) that produces salicyl benzoate from benzoyl-CoA and salicyl alcohol (Chedgy et al., 2015).