Serine hydrolase involved in the detoxification of formaldehyde. Hydrolyzes S-formylglutathione to glutathione and formate. Shows also esterase activity against alpha-naphthyl acetate, lactoylglutathione, palmitoyl-CoA and several pNP-esters of short chain fatty acids. H2O + S-formylglutathione = formate + glutathione + H(+) Inhibited by the sulfhydryl inhibitors (N-ethylmaleimide, iodoacetate, ZnCl(2) and CuCl(2)). Homotetramer. Constitutively expressed. Belongs to the esterase D family.