Metabolism of [5-h]proline by barley leaves and its use in measuring the effects of water stress on proline oxidation.
Metabolism of [5-h]proline by barley leaves and its use in measuring the effects of water stress on proline oxidation.
复制标题
大麦叶对[5-h]脯氨酸的代谢及其在测量水分胁迫对脯氨酸氧化的影响中的应用。
DOI：
10.1104/pp.61.4.654
复制
发表时间：
1978
期刊：
影响因子：
7.4
通讯作者：
S. F. Boggess
中科院分区：
文献类型：
--
作者：
C. Stewart;S. F. Boggess
这些实验的目的是从脯氨酸的5位确定氚的命运，并评估其损失到H(2)O作为脯氨酸氧化测量的有效性。在大麦（Hordeum vulgare）叶片中添加[5-(3)H]脯氨酸后，氚在H(2)O和谷氨酸、谷氨酰胺、有机酸、天冬氨酸、天冬酰胺和γ -氨基丁酸等代谢产物中被回收。这些代谢物是脯氨酸的氧化产物，在5小时后恢复的(3)H中占8%。尽管在代谢物中回收了大量的脯氨酸，但通过测量从[5-(3)H]脯氨酸中回收(3)H(2)O来估计的脯氨酸氧化速率仅略低于通过将（14）C并入氧化产物和从总脯氨酸中损失（14）C来估计的速率。因此，[5-(3)H]脯氨酸的H(2)O恢复有助于评估应激对脯氨酸代谢的影响。如前所述，水分胁迫抑制脯氨酸氧化。此外，在胁迫叶片中，脯氨酸氧化产物再转化为脯氨酸。这一观察结果可能表明脯氨酸合成和脯氨酸氧化的细胞区隔被破坏。
The objective of these experiments was to determine the fate of tritium from the 5 position of proline and to assess the validity of its loss to H(2)O as a measure of proline oxidation. When [5-(3)H]proline was fed to barley (Hordeum vulgare) leaves, tritium was recovered in H(2)O and metabolites such as glutamate, glutamine, organic acids, aspartate, asparagine, and gamma-aminobutyrate. Collectively these metabolites, which are oxidation products of proline, accounted for 8% of the (3)H recovered after 5 hours. In spite of the amount recovered in metabolites, the rates of proline oxidation estimated by measuring (3)H(2)O recovery from [5-(3)H]proline were only slightly lower than rates estimated by incorporation of (14)C into oxidized products and loss of (14)C from total proline. Therefore, (3)H(2)O recovery from [5-(3)H]proline is useful in assessing the effects of stress on proline metabolism.Water stress inhibited proline oxidation, as reported previously. In addition, a reconversion of proline oxidation products to proline occurred in stressed leaves. This observation probably indicates a breakdown in cellular compartmentation of proline synthesis and proline oxidation.