Toelzer et al. showed that MekB (9psed-q0mrg5) from Pseudomonas veronii and CgHle (corgl-CGL0839) from Corynebacteriumglutamicum are esterases that hydrolyse preferentially acetic acid esters. MekB and CgHle cannot bind homoserine and acetyl-CoA. Accordingly a novel esterase subfamily was extracted from the Homoserine_transacetylase family