Under heavy metal stress,higher plants initiate a set of defense responses,among which biosynthesis of phytochelatins (PCs) is important. PCs are rich in cystein and biosynthesized by phytochelatin synthase. The chemi...Under heavy metal stress,higher plants initiate a set of defense responses,among which biosynthesis of phytochelatins (PCs) is important. PCs are rich in cystein and biosynthesized by phytochelatin synthase. The chemical structure of PCs and their ability to form complexes with a large range of metal ions is clear. Up to now,these peptides are known to play an important role in both endogenous metal ion homeostasis and heavy metal ion detoxification. The mechanism of cadmium tolerance is illustrated in detail. A model of this mechanism suggested that the detoxification process of cadmium include such steps as PCs induction,transport of cadmium into the tonoplast,formation of the HMW-Cd-PCs complexes and sequestration in vacuole. At the same time,PCs also have other functions,such as detoxification of arsenic,protecting enzyme from metal ion inhibition and supplying metal ion as a cofactor to the enzyme potentially. However,a lot of questions about its biological function remain to be answered. In 1999,three independent labs isolated the genes encoding the PCs synthase. This breakthrough of plant heavy metal tolerance research gave us a chance to further study the heavy metal tolerance mechanism. All the results from the reserch of PCs have a great application potential in phytoremidation. Fig 1,Ref展开更多
考察不同 p H值下金属硫蛋白与锌 (Zn)的结合情况表明 ,p H值下降 ,总离子流强度增大 ,但低于 3以后 ,又急剧下降 ;同时 p H也决定了金属与硫蛋白的结合形态 ,在比较理想的电离的条件下发现 ,在 p H 3 .0时主要以脱金属硫蛋白的形式存...考察不同 p H值下金属硫蛋白与锌 (Zn)的结合情况表明 ,p H值下降 ,总离子流强度增大 ,但低于 3以后 ,又急剧下降 ;同时 p H也决定了金属与硫蛋白的结合形态 ,在比较理想的电离的条件下发现 ,在 p H 3 .0时主要以脱金属硫蛋白的形式存在 ;在 p H4.0时金属硫蛋白结合了 4个 Zn。展开更多
With the pollution of heavy metals becoming more and more serious, hu- man health suffers from great harms, making the detoxification in human body admit of no delay. This paper summarized the heavy metals used for de...With the pollution of heavy metals becoming more and more serious, hu- man health suffers from great harms, making the detoxification in human body admit of no delay. This paper summarized the heavy metals used for detoxification in hu- man body in recent years, including metallothionein, polyphenols, dietary fibers from seaweed, GTS, and explored the detoxification mechanism of these heavy metals in human body.展开更多
文摘Under heavy metal stress,higher plants initiate a set of defense responses,among which biosynthesis of phytochelatins (PCs) is important. PCs are rich in cystein and biosynthesized by phytochelatin synthase. The chemical structure of PCs and their ability to form complexes with a large range of metal ions is clear. Up to now,these peptides are known to play an important role in both endogenous metal ion homeostasis and heavy metal ion detoxification. The mechanism of cadmium tolerance is illustrated in detail. A model of this mechanism suggested that the detoxification process of cadmium include such steps as PCs induction,transport of cadmium into the tonoplast,formation of the HMW-Cd-PCs complexes and sequestration in vacuole. At the same time,PCs also have other functions,such as detoxification of arsenic,protecting enzyme from metal ion inhibition and supplying metal ion as a cofactor to the enzyme potentially. However,a lot of questions about its biological function remain to be answered. In 1999,three independent labs isolated the genes encoding the PCs synthase. This breakthrough of plant heavy metal tolerance research gave us a chance to further study the heavy metal tolerance mechanism. All the results from the reserch of PCs have a great application potential in phytoremidation. Fig 1,Ref
文摘考察不同 p H值下金属硫蛋白与锌 (Zn)的结合情况表明 ,p H值下降 ,总离子流强度增大 ,但低于 3以后 ,又急剧下降 ;同时 p H也决定了金属与硫蛋白的结合形态 ,在比较理想的电离的条件下发现 ,在 p H 3 .0时主要以脱金属硫蛋白的形式存在 ;在 p H4.0时金属硫蛋白结合了 4个 Zn。
基金Supported by the National Key Technology R&D Program(2013BAD10B03)National High-tech R&D Program of China(2011AA100901)the National Natural Science Foundation of China(31201340,31201402)~~
文摘With the pollution of heavy metals becoming more and more serious, hu- man health suffers from great harms, making the detoxification in human body admit of no delay. This paper summarized the heavy metals used for detoxification in hu- man body in recent years, including metallothionein, polyphenols, dietary fibers from seaweed, GTS, and explored the detoxification mechanism of these heavy metals in human body.
文摘[目的]在不同p H范围内和不同时间下检测重组Hc MT结合的锌、铜离子的含量,对金属离子竞争结合金属硫蛋白的特征进行分析。[方法]构建重组表达载体,将重组质粒p ET-32a-Hc MT进行原核表达,诱导时加入Zn2+,获得菌体后超声破碎,上清中添加Cu2+,分离纯化融合蛋白Trx A-Hc MT,检测金属硫蛋白溶液紫外吸收情况。样品硝化后用ICP-OES检测金属硫蛋白结合的金属离子含量。[结果]在p H 3~9的范围内,重组Hc MT上结合的Zn2+含量随着p H值升高而升高。加入Cu2+后,重组Hc MT上结合的Cu2+浓度上升,Zn2+浓度下降。在p H 3时,重组Hc MT结合金属离子的比值Cu2+/Zn2+为最小值0.68,在p H 8时Cu2+/Zn2+为最大值1.48,有利于Cu2+竞争。当p H 8时,不同时间下Zn-Hc MT与Cu2+的竞争结果表明1 h时锌铜有竞争高峰。[结论]证明了铜离子可以取代结合在重组HcMT上的锌离子,在p H 7~9范围中结合1 h竞争效率最高,该研究为重组Hc MT在重金属解毒方面的应用奠定基础。
