Kallikrein 4（KLK4） is a protease expressed during the transition and maturation stages of dental enamel formation. KLK4 can degrade enamel proteins, reduce enamel proteins combination to hydroxyapatite, and promote the enamel crystals growth and mineralization. KLK4 mutations or defects cause hypomaturation amelogenesis imperfecta. This article reviewed the structure, expression, functions, regulatory factors of KLK4 and its effect on amelogenesis imperfecta.
