Serum paraoxonase/arylesterase 1 and Serum paraoxonase/lactonase 3 (PON1 and PON3 respectively) were identified as the major enzymes involved in the hydrolysis of atorvastatin-lactone (ATVL) to atorvastatin (ATV) in human liver (Riedmaier et al. 2011). They are predominantly associated with the ER membrane (Gonzalvo et al. 1998, Riedmaier et al. 2011). It is very likely that these two enzymes also convert the corresponding 4-hydroxyl-metabolite.
acyl-L-homoserine-lactone lactonohydrolase activity of PON1,3:2xCa2+ dimers [endoplasmic reticulum membrane]