Cohen-Solal L, Cohen-Solal M, Glimcher M J
Proc Natl Acad Sci U S A. 1979 Sep;76(9):4327-30. doi: 10.1073/pnas.76.9.4327.
Purified components of chicken bone collagen contain approximately 4 atoms of organic phosphorus per mol of collagen, located principally in the alpha 2 chains. Previous analyses have demonstrated the absence of O-phosphoserine, O-phosphothreonine, and other phosphorylated hydroxy amino acids, phosphoamidated amino acids, and phosphorylated sugars. In the present report we establish that chicken bone collagen contains gamma-glutamyl phosphate. This was accomplished by the isolation of tritiated alpha-amino-delta-hydroxyvaleric acid after reductive cleavage with NaB[3H]H4 of the gamma components, the alpha 2 chains, and peptides enriched in organic phosphorus that were derived from the alpha 2 chains. Tritiated alpha-amino-delta-hydroxyvaleric acid was not detected in any of the following unphosphorylated proteins after cleavage with NaB[3H]H4:albumin and lysozyme, the alpha 2 chains of several unmineralized tissues, and, most importantly, dephosphorylated alpha 2 chains of chicken bone collagen. The alpha 2 chain of chicken bone collagen is the first structural protein found to contain an acyl phosphate.
鸡骨胶原蛋白的纯化成分每摩尔胶原蛋白含有约4个有机磷原子，主要位于α2链中。先前的分析表明不存在O-磷酸丝氨酸、O-磷酸苏氨酸以及其他磷酸化羟基氨基酸、磷酰胺化氨基酸和磷酸化糖。在本报告中，我们确定鸡骨胶原蛋白含有γ-谷氨酰磷酸。这是通过用NaB[3H]H4对γ成分、α2链以及富含源自α2链的有机磷的肽进行还原裂解后，分离出氚化的α-氨基-δ-羟基戊酸来实现的。在用NaB[3H]H4裂解后，在以下任何一种未磷酸化的蛋白质中均未检测到氚化的α-氨基-δ-羟基戊酸：白蛋白和溶菌酶、几种未矿化组织的α2链，以及最重要的是鸡骨胶原蛋白的去磷酸化α2链。鸡骨胶原蛋白的α2链是发现的首个含有酰基磷酸的结构蛋白。
