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首页> 外文期刊>The biochemical journal >Prolyl-tRNA-based rates of protein and collagen synthesis in human lung fibroblasts
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Prolyl-tRNA-based rates of protein and collagen synthesis in human lung fibroblasts

机译：基于蛋白质的蛋白质和胶原蛋白合成的蛋白质和胶原合成率

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pKnowledge of the dynamics of collagen turnover requires information regarding rates of synthesis of this group of connective-tissue proteins. The relationship of various amino acid pools to the tRNA precursor pool used for protein synthesis is known to vary between different cell types and tissues, even for essential amino acids. We studied extracellular, intracellular and tRNA-proline pools in cultured human lung IMR-90 fibroblasts to determine the relationship between them as candidate proline precursor pools for total protein and collagen synthesis. Time-course experiments showed that the three proline pools attained distinctly different steady-state specific radioactivities (extracellular greater than intracellular greater than tRNA) at the extracellular proline concentration of 0.2 mM. The kinetics of radioisotope incorporation into cell protein and collagenase-digestible protein indicated that the intracellular free proline pool could not be used reliably as a precursor for calculating synthetic rates. However, tRNA-proline behaved isotopically as if it were the precursor and provided synthesis rates 2-3-fold higher than those calculated by using either free proline pool. The incorporation of labelled lysine and leucine was constant over a wide range of extracellular proline concentrations. Fractional rates of protein synthesis based on tRNA-amino acid were the same with [3H]phenylalanine as with [3H]proline. The specific radioactivity of cell-associated hydroxyproline reached a steady-state value 8-10h after radioisotope administration which matched the mean tRNA-proline specific radioactivity, suggesting that tRNA-proline is not isotopically compartmentalized. A model of cellular proline-pool relationship is presented and discussed./p
机译：

胶原蛋白的动态知识需要关于该组结缔组织蛋白的合成率的信息。已知各种氨基酸池与用于蛋白质合成的TRNA前体池的关系在不同的细胞类型和组织之间，即使对于必需的氨基酸，也可以在不同的细胞类型和组织之间变化。我们研究了培养的人肺IMR-90成纤维细胞中的细胞外，细胞内和TRNA-脯氨酸池，以确定它们之间的关系作为总蛋白质和胶原合成的候选脯氨酸前体池。时间课程实验表明，在细胞外脯氨酸浓度为0.2mm的细胞外脯氨酸浓度下，三种脯氨酸池率明显不同的稳态特异性放射性（细胞外大于细胞内大于TRNA）。放射性同位素掺入到细胞蛋白和胶原酶可消化蛋白中的动力学表明，细胞内游离脯氨酸池不能可可靠地用作计算合成率的前体。然而，TRNA-脯氨酸在同位素上表现出，好像它是前体，并且提供的合成率高于通过使用游离脯氨酸池计算的那些高2-3倍。掺入标记的赖氨酸和亮氨酸在各种细胞外脯氨酸浓度上是恒定的。基于TRNA-氨基酸的蛋白质合成的分数率与[3H]苯丙氨酸与[3H]脯氨酸相同。细胞相关羟基脯氨酸的特定放射性达到稳态值8-10h，达到平均TRNA-脯氨酸特异性放射性匹配，表明TRNA-脯氨酸在不同时划分。呈现和讨论了细胞脯氨酸池关系模型。

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