Regulation of C4 Photosynthesis: Inactivation of Pyruvate,Pi Dikinase in Leaf and Chloroplast Extracts in Relation to Dark/Light Regulation in Vivo
Regulation of C4 Photosynthesis: Inactivation of Pyruvate,Pi Dikinase in Leaf and Chloroplast Extracts in Relation to Dark/Light Regulation in Vivo
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C4 光合作用的调节：叶和叶绿体提取物中丙酮酸、Pi 二激酶的失活与体内暗/光调节的关系
DOI：
10.1093/oxfordjournals.pcp.a076137
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发表时间：
1981
影响因子：
4.9
通讯作者：
M. Hatch
中科院分区：
文献类型：
--
作者：
T. Sugiyama;M. Hatch
从受光照的叶子中分离出的叶子或叶绿体提取物中的活性丙酮酸、P1二激酶通过与 ADP 一起孵育而失活。对于叶绿体提取物，单独使用 ATP 或 AMP 均无效。使用约 55 μM ADP 观察到最大失活率的一半。以下证据支持 ADP 介导的失活同时需要低浓度 ATP 的观点 [Buchanan (1980)Ann. Rev. Plant Physiol.31: 341]，添加己糖激酶和葡萄糖可防止 ADP 失活 [Feldhaus 等人。 (1975) 欧洲。 J. Biochem.57: 197]，当添加 GDP 和 UDP 代替 ADP 时，仅当同时提供 ATP 时，它们才会介导快速失活； GTP 没有效果。 ATP 在约 1 μM 或更低时显然具有最佳效果。失活率大约与提取物浓度的平方成正比，这表明除活性酶外还取决于提取物中的因素。通过提取物的胰蛋白酶处理证实了一种或多种热不稳定蛋白因子的参与。丙酮酸、通过 ADP 处理失活的 P1 二激酶通过与 P1 一起孵育而重新激活，这是从深色叶子中提取的失活酶所共有的特性。硫醇/二硫化物相互转化对于丙酮酸、P1二激酶的调节显然并不重要。
Active pyruvate, P1dikinase in leaf or chloroplast extracts isolated from illuminated leaves was inactivated by incubating with ADP. With chloroplast extracts neither ATP nor AMP alone was effective. Half the maximum rate of inactivation was observed with about 55 μM ADP. The following evidence supported the view that ADP-mediated inactivation had a co-requirement for low concentrations of ATP [Buchanan (1980)Ann. Rev. Plant Physiol.31: 341], adding hexokinase and glucose prevented inactivation by ADP [Feldhaus et al. (1975)Eur. J. Biochem.57: 197], when GDP and UDP were added in place of ADP they mediated rapid inactivation only when ATP was also provided; GTP was not effective. ATP was apparently optimally effective at about 1 μM or less. The rate of inactivation was approximately proportional to the square of extract concentration suggesting dependancy on a factor in the extracts in addition to active enzyme. The involvement of one or more heat labile protein factors was confirmed by trypsin treatment of extracts. Pyruvate, P1dikinase inactivated by treatment with ADP was reactivated by incubating with P1, a property common to the inactive enzyme extracted from darkened leaves. Thiol/disulphide interconversion was apparently not critical in the regulation of pyruvate, P1dikinase.