The organic matrix of the developing enamel is highly heterogeneous, comprising proteins derived from a number of different genes, including amelogenin, enamelin, ameloblastin, tuftelin, dentine sialophosphoprotein, enzymes and serum proteins. Each of these classes appears to undergo post-secretory sequential degradation which contributes towards further matrix heterogeneity. Possible functions of these proteins are discussed. Proteins of the organic matrix are presumed to play an important role in the modulation of mineral deposition and growth during tooth morphogenesis but the precise functions of individual matrix proteins remain unclear. (Tab. 1, Fig. 2, Ref. 47).