CES1G, also known as liver carboxylesterase 1, is a member of a large family of carboxylesterases that are responsible for the hydrolysis of ester and amide bonds. CES1G shares the serine hydrolase fold observed in other esterases. It is a rat and mouse specific protein that is expressed predominantly in liver, but also in kidney and lung. Recombinant mouse CES1G, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.