Studies on the matrix resicles of the odontoblast layer and cementoblast layer of bovine tooth germs.

Matrix vesicles are extracelluar organelles that initiate mineralization in the extracelluler Matrixof various calcifing tissues. The dentin was removed from bovine tooth germs. The matrix vesiclefractions, obtained by collagenase digestion and differential centrifugation被subjected to sucrose-density-gradient centrifugation. Alkaline phosphatase activity（ALP）protease activity,lactate dehydrogenase activity (LDH) assayed for the marker enzyme of matrix vesicles.1.There were not only the matrix vesicle but also matrix vesicle-like-vesicle with a high density inthe dentin,vesicle contained ALP and LDH but did not protease.2. protease activity after inhibition witho-phenanthroline was restored by the addition of Co D12+ Zn D12+ ZnThese results show that the protese in the matrix vesicles of the odontoblasts and predentin is anietalloprotese.3. Aldolase, aspartate: 2-oxoglutarate aminotransferase and alanine：2 - oxoglutarate aminotransferase, cytosonic enzymes except ldh, were not detected in these vesicles。这些results suggest the presence of a mechanism for the specific uptake of cytosolic LDH。

Matrix vesicles are extracelluar organelles that initiate mineralization in the extracelluler matrix of various calcifing tissues. The dentin was removed from bovine tooth germs. The matrix vesicle fractions, obtained by collagenase digestion and differential centrifugation, were subjected to sucrose-density-gradient centrifugation. Alkaline phosphatase activity(ALP) , protease activity, and lactate dehydrogenase activity (LDH) were assayed for the marker enzyme of matrix vesicles.1. There were not only the matrix vesicle but also matrix vesicle-like-vesicle with a high density in the dentin, the vesicle contained ALP and LDH but did not protease.2. Protease activity after inhibition with o-phenanthroline was restored by the addition of CoィイD12+ィエD1 and ZnィイD12+ィエD1, These results show that the protese in the matrix vesicles of the odontoblasts and predentin is a nietalloprotese.3. Aldolase, aspartate : 2-oxoglutarate aminotransferase and alanine : 2-oxoglutarate aminotransferase,cytosonic enzymes except LDH ,were not detected in these vesicles. These results suggest the presence of a mechanism for the specific uptake of cytosolic LDH.