Purification and properties of pig liver esterase

A homogenous preparation of pig liver aliesterase (EC 3.1.1.1) was obtained by the use of preparative starch-gel electrophoresis. The esterolytic activity of this preparation is markedly accelerated at high substrate concentration. Two active sites on the molecule may account for this unusual kinetic behavior. The sites may be identical as in a monomer-dimer equilibrium or they may be nonidentical and different in function. The esterase apparently is neither stereospecific nor stereoselective, and it did not exhibit an asymmetric active site. The enzyme hydrolyzes esters that are nonionic at a much greater rate than charged analogs. Half-esters of dicarboxylic acids are neither substrates nor inhibitors. Apparently an anionic charge on an ester inhibits the association between the esterase and ester.