DIFFERENCES IN COMPOSITION OF CELL-ATTACHMENT SIALOPROTEINS BETWEEN DENTIN AND BONE

Matrices of dentin and bone were compared with respect to the content of cell-attachment sialoproteins. The levels of two sialoproteins, ost eopontin (OPN)and bone sialoprotein (BSP), were determined in dentin a nd bone by immunochemical procedures. Polyclonal antibodies against bo vine BSP and an antibody against the amino-terminal decapeptide of rat OPN were used. The relative levels of OPN and BSP in dentin were less than one-tenth of the levels in bone. The differences between dentin and bone levels of OPN and BSP were thus larger than those for osteone ctin or bone Gla protein in the two tissues. The scarcity of the cell- attachment proteins in dentin may reflect the metabolic inactivity of dentin.