Amelx (amelogenin X chromosome) is an extracellular matrix protein secreted by ameloblasts and is a major component of enamel matrix. The Amelogenin plays a role in the biomineralization of teeth. It seems to regulate the formation of crystallites during the secretory stage of tooth enamel development. The protein is also thought to play a major role in the structural organization and mineralization of developing enamel. Recently, in addition to their role in enamel formation, the biological activity of enamel proteins in the process of cell differentiation has recently become widely appreciated.