Ureide metabolism in leaves of nitrogen-fixing soybean plants.
Ureide metabolism in leaves of nitrogen-fixing soybean plants.
复制标题
固氮大豆植物叶片中的脲化物代谢。
DOI：
10.1104/pp.77.3.779
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发表时间：
1985
期刊：
影响因子：
7.4
通讯作者：
Robert J. Ireland
中科院分区：
文献类型：
--
作者：
B. Shelp;Robert J. Ireland
在大豆叶片中，在黑暗中[14] C]尿素依赖的NH（3）和（14）CO（2）的产生显示出约2：1的化学计量比，并且在存在50毫摩尔乙酰异羟肟酸（一种脲酶抑制剂）的情况下，减少到低于对照组（每克鲜重每小时12-19微摩尔NH（3））的11%。利用[2-（14）C]尿囊素产生的NH（3）和CO（2）也表现出2：1的化学计量比，并且由于乙酰异羟肟酸盐的存在而减少到类似的程度，伴随着尿素的积累，这完全解释了NH（3）产生的损失。从尿囊素和尿素代谢中产生的NH（3）和CO（2）对乙酰异羟肟酸几乎完全敏感，加上观察到的化学计量，表明酰脲同化途径（每小时每克叶鲜重2.0微摩尔）通过尿囊酸、脲基乙醇酸和乙醛酸产生两个尿素分子，依次产生四个NH（3）分子和两个CO（2）分子。
In leaf pieces from nodulated soybean (Glycine max [L] Merr cv Maple Arrow) plants, [(14)C]urea-dependent NH(3) and (14)CO(2) production in the dark showed an approximately 2:1 stoichiometry and was decreased to less than 11% of the control (12-19 micromoles NH(3) per gram fresh weight per hour) in the presence of 50 millimolar acetohydroxamate, a urease inhibitor. NH(3) and CO(2) production from the utilization of [2-(14)C] allantoin also exhibited a 2:1 stoichiometry and was reduced to a similar extent by the presence of acetohydroxamate with a concomitant accumulation of urea which entirely accounted for the loss in NH(3) production. The almost complete sensitivity of NH(3) and CO(2) production from allantoin and urea metabolism to acetohydroxamate, together with the observed stoichiometry, indicated a path of ureide assimilation (2.0 micromoles per gram leaf fresh weight per hour) via allantoate, ureidoglycolate, and glyoxylate with the production of two urea molecules yielding, in turn, four molecules of NH(3) and two molecules of CO(2).