Biochemical comparisons of matrix proteins extracted from healthy human alveolar bone, dentin and cementum

Matrix proteins of bone, dentin and cementum have been shown to play a role in bone induction during the mineralization process, and in regulating the activities of several types of mesenchymal cells. Whether these biological functions are mediated through the same mechanism or whether there is specific modulation in each biological process is still open to speculation. The purpose of this pilot investigation was to compare the non-collagenous proteins among these tissues. Bone and teeth, obtained from clinically healthy subjects, were sectioned into 1 mm thick pieces. With the aid of a dissecting microscope, cementum and dentin were separated and collected. Tissue specimens were extracted sequentially in three steps by solutions containing 0.5 M acetic acid, 4 M Guanidine/0.5 M EDTA, and 250 units/ml bacterial collagenase, respectively. Proteins extracted were dialyzed, lyophilized and then further analyzed by both 10% SDS-PAGE (1-D) and two-dimensional (2-D) SDS-PAGE. Comparison showed that the three extraction buffers had relatively different extraction capacities within and among each tissue. The components extracted by acetic acid and Guanidine/EDTA were similar, but seemed different from that extracted by bacterial collagenase as shown by 10% SDS-PAGE. Two-dimensional SDS-PAGE further characterized numerous distinct protein spots from bone (MW of 61, 55, 40, 35, 34, 33 kD and eleven distinct spots which showed MW between 10 and 29 kD, pI range of 5.6-6.4), dentin (MW of 59, 54, 35, 28, 25, 24, 21 kD), and cementum (MW of 71, 64-65, 58, 55, 52, 50, 47, 43, 40, 31, 19 kD).(ABSTRACT TRUNCATED AT 250 WORDS)