Acidic phosphorylated proteins have been shown to be prominent constituents of the
extracellular matrix of bone and dentin. The acidic phosphoproteins of bone contain more
glutamic acid than aspartic acid and a lower serine content than either. On the other hand,
the major dentin acidic phosphoproteins, phosphophoryns, have been defined as aspartic
acid-and serine-rich proteins, with a lesser content of glutamic acid. Both sets of
phosphoproteins have been implicated as key participants in regulating mineralization, but it …