BIOCHEMISTRY AND MINERALIZATION OF TOOTH CEMENTUM

这些研究的目的是为了获得一个基本的了解， 细胞外基质成分的结构和组织 牛牙骨质及其在矿化中的潜在作用。的 最丰富的有机组分的详细结构，I型 胶原蛋白，将通过定量的分子分布进行研究， 共价分子间交联和它们的前体醛， 胶原纤维这将通过定量分析这些 化合物和确定它们在原纤维内的分子位点， 从NaB 3 H4还原的组织中分离这些肽。基于 数据，我们可以获得有关特定三维的信息， 牙骨质胶原纤维的结构，这是必不可少的 稳定组织，并在组织的 成矿这些数据将与牙本质和 从相同的牙齿和颌骨上得到的齿槽骨。我们还将隔离 并研究这种组织中主要磷蛋白的结构， 矿化的潜在成核剂，也存在于EDTA可溶性 作为不溶性部分。后一级分中的磷蛋白是 与矿物质和不溶性胶原纤维密切相关。的 新描述的磷蛋白相关的分子起源 双功能交联，组氨酸丙氨酸和赖氨酸丙氨酸，以及它们的 分子组织中的功能意义将由 分离交联的肽并鉴定 这些化合物在肽中。此外，主要的蛋白聚糖， 另一种阴离子组分将被分离并通过琼脂糖分析， 聚丙烯酰胺凝胶电泳，并进行了详细的 使用大组单克隆抗体进行生物化学/免疫化学分析 针对结缔组织上存在的表位的抗体 蛋白聚糖 免疫组织化学技术也将被用来检查他们的组织 分布及其与胶原纤维的潜在相互作用 网络与牙骨质矿化有关。最后，归纳 速率、生长速率和矿物的局部化 牙骨质中的蛋白质（磷蛋白和蛋白聚糖）固定在 将在TEM水平上研究和比较不溶性胶原原纤维。这 这类研究将提供有关这些参与的信息， 矿化过程中的大分子及其与胶原的相互作用 过程

These studies are directed towards obtaining a basic understanding of the structure and organization of the extracellular matrix components of the bovine tooth cementum and their potential role(s) in mineralization. The detailed structure of the most abundant organic component, type I collagen, will be studied by quantifying the molecular distribution of the covalent intermolecular cross-links and their precursor aldehydes in the collagen fibrils. This will be performed by quantitative analysis of these compounds and determination of their molecular loci within the fibril by isolating these peptides from the NaB3H4-reduced tissue. Based on the data, we can obtain information concerning the specific three-dimensional structure of collagen fibrils of cementum which is essential for stabilization of the tissue and plays an important role in the tissue's mineralization. These data will be compared with those of dentin and alveolar bone obtained from the same teeth and jaws. We will also isolate and study the structure of the major phosphoproteins of this tissue, potential nucleators for mineralization, present in EDTA-soluble as well as insoluble fractions. The phosphoproteins in the latter fraction are strongly associated with mineral and insoluble collagen fibrils. The molecular origin of the newly described phosphoprotein-associated bifunctional cross-links, histidinoalanine and lysinoalanine, and their functional significance in molecular organization will be pursued by isolating the cross-linked peptides and identifying the molecular loci of these compounds within the peptides. In addition, the major proteoglycans, another anionic component, will be isolated and analyzed by agarose- polyacrylamide gel electrophoresis and subjected to detailed biochemical/immunochemical analysis with the large panel of monoclonal antibodies directed against epitopes present on connective tissue proteoglycans. Immunohistochemical techniques will also be used to examine their tissue distribution and their potential interaction with collagen fibrillar network in relation to mineralization of cementum. Finally, the induction rates, growth rates and localization of mineral induced by those anionic proteins in cementum (phosphoproteins and proteoglycans) immobilized on insoluble collagen fibrils will be studied and compared on TEM level. This type of study will provide information concerning the involvement of these macromolecules and their interactions with collagen in the mineralization process.