Ces1d, also known as carboxylesterase 1D, is a member of a large family of carboxylesterases that are responsible for the hydrolysis of ester and amide bonds. It is the principle lipase of white adipose tissue fat cake extracts. Partially purified white adipose tissue Ces1d had lipase activity as well as lesser but detectable neutral cholesteryl ester hydrolase activity. The protein shows low catalytic efficiency for hydrolysis of CPT-11, a prodrugs for camptothecin used in cancer therapeutics. Recombinant mouse Ces1d, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.