EFFECT OF HIGH-TEMPERATURE ON STARCH SYNTHESIS AND THE ACTIVITY OF STARCH SYNTHASE
EFFECT OF HIGH-TEMPERATURE ON STARCH SYNTHESIS AND THE ACTIVITY OF STARCH SYNTHASE
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DOI：
10.1071/pp9940783
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发表时间：
1994-01-01
期刊：
影响因子：
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通讯作者：
SMITH, AM
中科院分区：
文献类型：
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作者：
DENYER, K;HYLTON, CM;SMITH, AM
当谷物或马铃薯块茎等储存器官发育时，在高温下观察到的产量下降是由于最终淀粉含量降低所致。这些贮藏器官在高温下的发育过程中，淀粉的合成速度要么降低，要么不能充分增加，以补偿较短的发育时期。这种对淀粉合成速率的影响似乎不是由于光合产物供应的减少。淀粉合成途径中的一种酶，可溶性淀粉合成酶，在异常低温下容易热失活，也可能具有较低的最适温度以达到最大活性。在某些贮藏器官中，可溶性淀粉合成酶的最大催化活性并不比淀粉合成速率大很多。因此，这种酶活性的降低可能会影响淀粉合成的速度。因此，高温对淀粉合成速率的影响可能至少部分是由于这种酶的性质。本文就高温对贮藏器官中淀粉合成的影响这一背景下淀粉合酶异常的热敏性进行了综述。
The decrease in yield which is observed when developing storage organs such as cereal grains or potato tubers are exposed to high temperatures is due to a lower final starch content. The rate of starch synthesis during the development of these storage organs at high temperature, is either reduced or fails to increase sufficiently to compensate for the shorter developmental period. This effect on the rate of starch synthesis does not seem to be due to a reduction in the supply of photosynthate. One of the enzymes in the pathway of starch synthesis, soluble starch synthase, is susceptible to heat inactivation at unusually low temperatures and may also have a low optimum temperature for maximum activity. In some storage organs, the maximum catalytic activity of soluble starch synthase is not very much greater than the rate of starch synthesis. A decrease in the activity of this enzyme is therefore, likely to affect the rate of starch synthesis. Thus, the effect of high temperature on the rate of starch synthesis may be due, at least in part, to the properties of this enzyme. This review discusses the unusual heat-sensitivity of starch synthase in the context of the effects of high temperature on starch synthesis in storage organs.