Generation and use of recombinant human bone sialoprotein and osteopontin for hydroxyapatite studies.

Bone sialoprotein (BSP) and osteopontin (OPN) are two extracellular bone matrix proteins that have the ability to modulate the growth of hydroxyapatite in vitro. Studies of BSP/OPN hydroxyapatite interactions in the past have been directed toward the identification of essential structural elements that allow these two proteins to modulate hydroxyapatite growth. However, these studies are limited by the finite quantities of purified extracellular matrix proteins. I have utilized a recombinant E. coli expression system to obtain milligram quantities of human bone sialoprotein and human osteopontin that may be used to study extracellular matrix protein interactions with hydroxyapatite.