EXTRACELLULAR ALKALINE-PHOSPHATASE ACTIVITY IN MINERALIZING MATRICES OF CARTILAGE AND BONE - ULTRASTRUCTURAL-LOCALIZATION USING A CERIUM-BASED METHOD
EXTRACELLULAR ALKALINE-PHOSPHATASE ACTIVITY IN MINERALIZING MATRICES OF CARTILAGE AND BONE - ULTRASTRUCTURAL-LOCALIZATION USING A CERIUM-BASED METHOD
复制标题
DOI：
10.1007/bf00270033
复制
发表时间：
1992-05-01
期刊：
影响因子：
--
通讯作者：
BIANCO, P
中科院分区：
文献类型：
--
作者：
BONUCCI, E;SILVESTRINI, G;BIANCO, P
碱性磷酸酶(ALP)活性的超微结构定位于大鼠的生长骨、软骨和干骺端。在含有β-甘油磷酸盐、MgCl2和CeCl3的介质中孵育前，用EDTA脱钙和MgCl2处理以再生酶活性。成熟期和增生期软骨细胞和成骨细胞的质膜外表面有碱性磷酸酶的活性。此外，该反应产物还存在于软骨细胞陷窝、基质小泡、软骨基质以及骨样组织中未钙化的胶原纤维中。反应强度最低或完全缺乏，基质钙化程度最高。这些结果表明，碱性磷酸酶通过与基质小泡和质膜成分结合而从细胞转运到软骨和骨基质中，而且它在软骨和骨基质中的活性受到抑制，因为它被结合到矿物质中。
The ultrastructural localization of alkaline phosphatase (AlP) activity has been demonstrated in epiphyseal growth cartilage and metaphyseal bone of rats. Epiphyso-metaphyseal specimens were decalcified with EDTA and treated with MgCl2 to regenerate the enzymatic activity before incubation in a medium containing beta-glycerophosphate, MgCl2 and CeCl3. AlP activity was present on the outer surface of the plasmamembrane of maturing and hypertrophic chondrocytes and of osteoblasts. Moreover, the reaction product was present in chondrocyte lacunae, in matrix vesicles, and in cartilage matrix, as well as among uncalcified collagen fibrils of osteoid tissue in bone. The intensity of reaction was the lowest, or completely lacking, where the degree of matrix calcification was the highest. These results suggest that alkaline phosphatase is transported from the cells into the cartilage and bone matrix by its association with matrix vesicles and plasmamembrane components, and that its activity in cartilage and bone matrix is inhibited as it is incorporated in the mineral substance.