PHOSPHOPROTEIN OF DENTIN MATRIX
PHOSPHOPROTEIN OF DENTIN MATRIX
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DOI：
10.1021/bi00860a017
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发表时间：
1967-01-01
期刊：
影响因子：
2.9
通讯作者：
PERRY, A
中科院分区：
文献类型：
--
作者：
VEIS, A;PERRY, A
纯化的脱钙牛牙本质基质含有少量的结合磷，但似乎具有哺乳动物胶原蛋白的典型组成。结合的磷不能通过非水解或其他非降解性提取除去。延长氧化降解的基质与偏高碘酸钠导致约30%的基质的溶解，这部分含有超过75%的磷。分级溶解的牙本质导致在pH 5下分离出快速移动的、电泳均匀的阴离子组分（指定为F组分）。3.平衡超离心研究表明，F组分在分子量方面是均匀的，分子量为38，000 [±] 3000。分析表明F是一种蛋白质，每个分子含有大量的丝氨酸和天冬氨酸，加上少量的脯氨酸、羟脯氨酸和一个羟赖氨酸残基。F包含5。34个磷酸基团/分子的9%重量的P。由于羟基赖氨酸在高碘酸盐降解的条件下被破坏，除非羟基或[N]-氨基被封闭，并且由于F组分含有几乎所有在高碘酸盐降解中存活的牙本质的羟基赖氨酸，因此得出结论，F组分磷蛋白通过羟基赖氨酸侧链连接到胶原基质。磷蛋白占总基质重量的2%以下，或每四个胶原分子中少于一个。这种与胶原基质结合的高度阴离子磷蛋白可以为基质的矿化的外延成核提供位点。
Purified, decalcified bovine dentin matrix contains a small amount of bound phosphorus but otherwise appears to have a composition typical of mammalian collagens. The bound phosphorus cannot be removed by nonhydrolytic or other nondegradative extractions. Prolonged oxidative degradation of the matrix with sodium metaperiodate resulted in the solubilization of about 30% of the matrix and this portion contained more than 75% of the phosphorus. Fractionation of the solubilized dentin led to the isolation of a rapidly moving, electrophoretically homogeneous anionic component (designated F component) at pH 5. 3. Equilibrium ultra-centrifuge studies showed the F component to be homogeneous with respect to molecular weight and to have a molecular weight of 38, 000 [plus or minus] 3000. Analyses showed F to be a protein, containing unusually large amounts of serine and aspartic acid plus smaller amounts of proline, hydroxyproline, and one residue of hydroxylysine per molecule. F contained 5. 9% P by weight of 34 phosphate groups/molecule. Since hydroxylysine is destroyed under the conditions of periodate degradation unless either the hydroxyl or [epsilon]-amino group is blocked, and since the F component contained almost all of the hydroxylysine of the dentin which survived the periodate degradation it was concluded that the F component phosphoprotein is attached to the collagen matrix via the hydroxylysine side chain. The phosphoprotein comprises less than 2% of the total matrix on a weight basis or less than one molecule per four molecules of collagen. This highly anionic phosphoprotein, bound to the collagen matrix, may provide the sites for the epitactic nucleation of mineralization of the matrix.