Normal mature human enamel protein.

Pure enamel was prepared using an original microdissection technic. Protein concentration was 375 microgram per gram of enamel. Polyacrylamide gel electrophoresis showed a single fast-migrating zone containing a thin double band. Ultracentrifugation studies suggested that the proteins were of low molecular weight or of weak density. Absorption spectra showed a strong absorbance at 260nm. Amino acid analyses yielded a composition of 25% Gly, 13.5% Glu, 11% Ser, 11% Pro, 2% Cys and 2% Hyp. A glucidic content of 15% was estimated and glucose, galactose, mannose and fucose were identified. The organic matrix of enamel seemed to be constituted of two major glycoproteins probably fibrous but different from keratin.