Department of Plant Physiology, Waite Agricultural Research Institute, Glen Osmond, South Australia.
Plant Physiol. 1968 Jan;43(1):41-9. doi: 10.1104/pp.43.1.41.
A method is described for the extraction and measurement of soluble nucleotides from wheat grain. Nucleotides were separated (80-90% recovery) by paper chromatography followed by electrophoresis. The nucleotides extracted were ADP-glucose, ATP, ADP, AMP, and NAD; UDP-glucose, UTP, UDP, and UMP with smaller quantities of cytidine nucleotides.In grain sampled at 20 days after anthesis, 70% of the UDP-glucose was present in the endosperm and the remainder in the testa and pericarp; 90% of the ADP-glucose was found in the endosperm. Of the four uridine nucleotides UDP-glucose was the most plentiful and the level rose from about 330 mmumoles per g fresh weight on the third day after flowering to 430 mmumoles/g on day 12 and then fell steadily to about 140 mmumoles/g just before complete ripening. Levels of 250 mmumoles and 200 mmumoles per g fresh weight were recorded for UTP and UDP on day 12. Thereafter the content of UTP fell relatively more rapidly than either UDP or UDP-glucose.ATP was the most abundant adenine nucleotide and from 7 days after anthesis to day 40 the quantity per g fresh weight fell from about 350 mmumoles to 100 mmumoles. The level of ADP-glucose rose to a maximum of 140 mmumoles/g between days 15 and 21 and then fell slightly towards maturity while ADP varied between 50 and 80 mmumoles/g. On day 20, coinciding with the maximum rate of starch synthesis in the endosperm, the concentration of ADP-glucose in this tissue was about 0.3 mm, and that of UDP-glucose 0.7 mm.The relationship of these results to the mechanism of transfer of hexose units from sucrose to starch is discussed.
介绍了一种从小麦籽粒中提取和测量可溶核苷酸的方法。核苷酸通过纸层析（80-90%回收）后进行电泳分离。提取的核苷酸包括 ADP-葡萄糖、ATP、ADP、AMP 和 NAD；UDP-葡萄糖、UTP、UDP 和 UMP，还有少量的胞苷核苷酸。在授粉后 20 天取样的籽粒中，70%的 UDP-葡萄糖存在于胚乳中，其余部分存在于种皮和果皮中；90%的 ADP-葡萄糖存在于胚乳中。在四种尿嘧啶核苷酸中，UDP-葡萄糖最为丰富，其含量从开花后第三天的约 330 μmol/g 鲜重上升到第 12 天的 430 μmol/g，然后稳定下降到接近完全成熟时的约 140 μmol/g。第 12 天记录到 UTP 和 UDP 的含量分别为 250 μmol 和 200 μmol/g 鲜重。此后，UTP 的含量相对较快地下降，比 UDP 或 UDP-葡萄糖下降得都快。ATP 是最丰富的腺嘌呤核苷酸，从授粉后 7 天到第 40 天，每克鲜重的含量从约 350 μmol 下降到 100 μmol。ADP-葡萄糖的含量在第 15 天至第 21 天之间达到最大值 140 μmol/g，然后在成熟过程中略有下降，而 ADP 的含量在 50 和 80 μmol/g 之间波动。在第 20 天，正好是胚乳中淀粉合成速率的最大值，该组织中 ADP-葡萄糖的浓度约为 0.3 μmol，UDP-葡萄糖的浓度约为 0.7 μmol。这些结果与蔗糖中的己糖单位转移到淀粉的机制有关。
