CHI3L1, also known as chitinase-3-like protein 1, is a member of the glycosyl hydrolase 18 family. This protein can bind heparins, probably as heparin sulfate. It has been found to enhance cell adhesion and promote cell signaling, proliferation and tumor angiogenesis. Elevated serum CHI3L1 levels occur in some conditions characterized by inflammation and connective tissue remodeling such as arthritis, chronic obstructive pulmonary disease, diabetes, cardiovascular disease, inflammatory bowel disease, and liver cirrhosis. Recombinant human CHI3L1, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques