丙酮酸、磷酸二激酶的激活与失活机制研究。该酶在光合作用的C4二羧酸途径中可能的调节作用。

Studies on the mechanism of activation and inactivation of pyruvate, phosphate dikinase. A possible regulatory role for the enzyme in the C4 dicarboxylic acid pathway of photosynthesis.

作者信息

Hatch M D, Slack C R

出版信息

Biochem J. 1969 May;112(5):549-58. doi: 10.1042/bj1120549.

DOI:10.1042/bj1120549

PMID:5821721

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1187755/

Abstract

The activity of pyruvate,P(i) dikinase in leaves of maize and Amaranthus palmeri rapidly falls on transferring illuminated plants to darkness. Illumination of dark-treated plants results in an immediate rapid increase in activity of the enzyme, the final activity reached being dependent on the intensity of the incident light. 2. Activation of the enzyme in extracts of dark-treated maize leaves after gel filtration on Sephadex G-25 requires a thiol and P(i). The P(i) requirement for activation can be replaced by arsenate. Activation of the enzyme is inhibited by AMP and GMP and possibly also by ADP and ATP. Activation of the enzyme after gel filtration on Sephadex G-200 also requires a heat-labile component that is excluded by Sephadex G-25. 3. The active enzyme isolated from illuminated leaves is inactivated by ADP in the presence of a thiol, the rate of inactivation being very much faster in air than in an oxygen-free atmosphere. Reactivation of the ADP-inactivated enzyme requires a thiol, P(i) and a component excluded by Sephadex G-25 but considerably retarded by Sephadex G-200. 4. The active enzyme is rapidly and irreversibly inactivated in the absence of a thiol. Inactivation is accelerated by both sodium diethyldithiocarbamate and tetraethylthiuram disulphide, and the enzyme inactivated by these reagents is completely reactivated by incubation with dithiothreitol. This reactivation does not require P(i). The inactive enzyme from dark-treated leaves is stabilized by diethyldithiocarbamate and can be partially activated by dithiothreitol alone; complete reactivation requires both dithiothreitol and P(i). 5. The enzyme activity is markedly inhibited by the thiol reagents p-chloromercuribenzoate, gamma-(p-arsenophenyl)-n-butyrate and an equimolar mixture of arsenite and 2,3-dimercaptopropan-1-ol. 6. The processes of activation and inactivation observed in vitro are discussed in relation to the regulation of pyruvate,P(i) dikinase activity in the leaf.

摘要

将光照下的玉米和帕尔默苋叶片转移至黑暗环境中，丙酮酸、磷酸二激酶的活性迅速下降。对黑暗处理的植株进行光照，会使该酶的活性立即迅速增加，最终达到的活性取决于入射光的强度。2. 经葡聚糖凝胶G - 25凝胶过滤后的黑暗处理玉米叶片提取物中的该酶激活需要一种硫醇和磷酸。激活所需的磷酸可被砷酸盐替代。该酶的激活受到AMP和GMP的抑制，可能也受到ADP和ATP的抑制。经葡聚糖凝胶G - 200凝胶过滤后的该酶激活还需要一种热不稳定成分，而葡聚糖凝胶G - 25可将其排除。3. 在硫醇存在的情况下，从光照叶片中分离出的活性酶会被ADP灭活，在空气中的灭活速率比在无氧环境中快得多。ADP灭活酶的再激活需要一种硫醇、磷酸和一种被葡聚糖凝胶G - 25排除但被葡聚糖凝胶G - 200显著阻滞的成分。4. 在没有硫醇的情况下，活性酶会迅速且不可逆地失活。二乙基二硫代氨基甲酸钠和四乙基秋兰姆二硫化物都会加速失活，用这些试剂失活的酶通过与二硫苏糖醇孵育可完全再激活。这种再激活不需要磷酸。黑暗处理叶片中的无活性酶可被二乙基二硫代氨基甲酸钠稳定，仅用二硫苏糖醇即可部分激活；完全再激活需要二硫苏糖醇和磷酸。5. 该酶活性受到硫醇试剂对氯汞苯甲酸、γ -（对砷苯基）-正丁酸以及亚砷酸盐和2,3 -二巯基丙醇等摩尔混合物的显著抑制。6. 结合叶片中丙酮酸、磷酸二激酶活性的调节，讨论了体外观察到的激活和失活过程。