Chitinase 3-like 3 gene, also known as YM1 and ECF-L, encodes a precursor protein with 398 amino acid residues with a 21 residue signal sequence. Chitinase 3-like 3 protein is a lectin that binds saccharides with a free amino group, such as glucosamine or galactosamine. Binding to oligomeric saccharides is much stronger than binding to mono- or disaccharides. Also binds heparin and G1cN oligomers, and is produced primarily by macrophages during inflammation. It has chemotactic activity for T-lymphocytes, bone marrow cells and eosinophils.