Identification of organic phosphorus covalently bound to collagen and non-collagenous proteins of chicken-bone matrix. The presence of O-phosphoserine and O-phosphothreonine in non-collagenous proteins, and their absence from phosporylated collagen.
Identification of organic phosphorus covalently bound to collagen and non-collagenous proteins of chicken-bone matrix. The presence of O-phosphoserine and O-phosphothreonine in non-collagenous proteins, and their absence from phosporylated collagen.
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鸡骨基质胶原蛋白和非胶原蛋白共价结合有机磷的鉴定。
DOI：
10.1042/bj1770081
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
Melvin J. Glimcher
中科院分区：
文献类型：
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作者：
Lola Cohen;J. B. Lian;D. Kossiva;Melvin J. Glimcher
非胶原蛋白磷蛋白几乎全部都可以在蛋白酶抑制剂存在下在中性 pH 值的 EDTA 中提取，在鸡骨基质中被鉴定，因此不与胶原蛋白共价结合。同样，所有含有 γ-羧基谷氨酸的肽都存在于 EDTA 提取物中，而不溶性残留物中则没有，这证实没有任何肽与鸡骨胶原蛋白共价连接。然而，有机磷也被发现存在于鸡骨胶原蛋白中，主要存在于 α2 链中。鸡骨基质中存在的总蛋白质结合有机磷中，约。 80% 与非胶原蛋白相关，20% 与胶原蛋白相关。可溶性非胶原蛋白含有O-磷酸丝氨酸和O-磷酸苏氨酸，这些基本上构成了它们的有机磷含量。相反，胶原蛋白既不含 O-磷酸丝氨酸，也不含 O-磷酸苏氨酸。事实上，在纯化的胶原蛋白成分中没有鉴定出磷酸化羟基氨基酸、磷酸酰胺化氨基酸或磷酸化糖，每个胶原蛋白分子含有大约四到五个有机磷原子。含有机磷的肽是从纯化胶原蛋白成分的部分酸水解产物和酶消化物中分离出来的，其中含有尚未鉴定的阳离子氨基酸。这些数据、磷酸化肽中非常高浓度的谷氨酸以及完整胶原链中有机磷部分的pH稳定性强烈表明胶原中至少部分有机磷以磷酸化谷氨酸的形式存在。这表明鸡骨基质中含有有机磷的两种主要化学成分不同的蛋白质部分可能代表在单独的生物控制下两个不同的有机磷代谢库。
Non-collagenous phosphoproteins, almost all of which can be extracted in EDTA at neutral pH in the presence of proteinase inhibitors, are identified in the matrix of chicken bone, and are therefore not covalently bound to collagen. Similarly, all the peptides containing gamma-carboxyglutamic acid are present in the EDTA extract and none in the insoluble residue, confirming that none is covalently linked to chicken bone collagen. However, organic phosphorus is also found to be present in chicken bone collagen, principally in the alpha2-chains. Of the total protein-bound organic phosphorus present in chicken bone matrix, approx. 80% is associated with the non-collagenous proteins and 20% with collagen. The soluble non-collagenous proteins contain both O-phosphoserine and O-phosphothreonine and these account for essentially of their organic phosphorus content. In contrast, collagen contains neither O-phosphoserine nor O-phosphothreonine. Indeed, no phosphorylated hydroxy amino acid, phosphoamidated amino acid or phosphorylated sugar could be identified in purified components of collagen, which contain approximately four to five atoms of organic phosphorus per molecule of collagen. Peptides containing organic phosphorus were isolated from partial acid hydrolysates and enzymic digests of purified collagen components, which contain an as-yet-unidentified cationic amino acid. These data, the very high concentrations of glutamic acid in the phosphorylated peptides, and the pH-stability of the organic phosphorus moiety in intact collagen chains strongly suggest that at least part of the organic phosphorus in collagen is present as phosphorylated glutamic acid. This would indicate that the two major chemically different protein fractions in chicken bone matrix that contain organic phosphorus may represent two distinct metabolic pools of organic phosphorus under separate biological control.