Chitinases catalyze the hydrolysis of chitin, which is an abundant glycopolymer found in insect exoskeletons and fungal cell walls. The glycoside hydrolase 18 family of chitinases includes eight human family members. CHI3L1 is a glycoprotein member of the glycosyl hydrolase 18 family. The protein lacks chitinase activity and is secreted by activated macrophages, chondrocytes, neutrophils and synovial cells. This protein is thought to play a role in the process of inflammation and tissue remodeling. Recombinant human CHI3L1 protein was expressed with C-terminal myc-His-tag in CHO(chinese hamster ovary) cells using mammalian expression system and purified by using conventional chromatography techniques.