Chemokines are a family of structurally related cytokines, most of which are secreted proteins with a molecular weight of about 10kda. The alpha helix structure at the carboxyl end of these cytokines is responsible for preferentially binding to proteoglycans and extracellular matrix proteins on endothelial cells. There are four cysteine residues located in their highly conserved positions.
Based on the number and spacing of two to four highly conserved N-terminal cysteine residues, chemokines are classified into four different subfamilies: CXC, CC, XC, and CX3C.
