Plasma proteins present in human cortical bone: enrichment of the alpha2HS-glycoprotein

The spectrum of plasma proteins present in human cortical bone and permanent dentine has been determined. One plasma glycoprotein, the alpha2HS-glycoprotein, was found to be present at a high concentration in both bone and dentine and was shown to be concentrated in the mineralized tissues with respect to the other plasma proteins by factors of between 30 and 100. In this respect the alpha2HS-glycoprotein is analogous to the G2B-glycoprotein and alpha-glycoprotein of bovine and rabbit b one, respectively. The binding of alpha2HS-glycoprotein and albumin to calcium phosphates generated within serum samples has been studied at different serum:precipitate ratios. In each case all the alpha2HS-glycoprotein was removed from the samples and the alpha2HS-glycoprotein was concentrated with respect to albumin by factors ranging from 370 at the highest serum:precipitate ratio to 25 at the lowest ratio. The plasma alpha2HS-glycoprotein concentrations of patients with Paget's disease of bone were shown to be substantially lower than the normal range, with significant negative correlation between the alpha2HS-glycoprotein concentration and the plasma alkaline phosphatase activity.