CD38, also known as ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1, is a surface molecule which has been attributed the function of a signaling channel leading to cellular activation and proliferation, an ectoenzyme with multiple function as well as an inducer of Ca2+ mobilization from cytoplasmic stores. It also functions as a plasma membrane signaling receptor in leukocytes. On B cells, It acts as a coreceptor and modulates B cell receptor (BCR) signals. Recombinant human CD38, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.