新陈代谢进化中分子设计的优化：糖原分子
Optimization of molecular design in the evolution of metabolism: the glycogen molecule.
作者信息
Meléndez-Hevia E, Waddell T G, Shelton E D
机构信息
Departamento de Bioquímica, Facultad de Biología, Universidad de La Laguna, Tenerife, Canary Islands, Spain.
出版信息
Biochem J. 1993 Oct 15;295 ( Pt 2)(Pt 2):477-83. doi: 10.1042/bj2950477.
The animal glycogen molecule has to be designed in accordance with its metabolic function as a very effective fuel store allowing quick release of large amounts of glucose. In addition, the design should account for a high capacity of glucose storage in the least possible space. We have studied the optimization of these variables by means of a mathematical model of the glycogen molecule. Our results demonstrate that the structure is optimized to maximize (a) the total glucose stored in the smallest possible volume, (b) the proportion of it that can be directly released by phosphorylase before any debranching occurs, and (c) the number of non-reducing ends (points of attack for phosphorylase), which maximizes the speed of fuel release. The optimization of these four variables is achieved with appropriate values for two key parameters in glycogen design: the degree of branching and the length of the chains. The optimal values of these two parameters are precisely those found in cellular glycogen.
动物糖原分子的设计必须与其代谢功能相一致，作为一种非常有效的燃料储备，能够快速释放大量葡萄糖。此外，该设计应考虑在尽可能小的空间内实现高容量的葡萄糖储存。我们通过糖原分子的数学模型研究了这些变量的优化。我们的结果表明，该结构经过优化，以实现以下几点的最大化：(a) 在尽可能小的体积内储存的总葡萄糖量；(b) 在任何脱支发生之前可被磷酸化酶直接释放的葡萄糖比例；(c) 非还原端的数量（磷酸化酶的攻击点），这使燃料释放速度最大化。通过糖原设计中两个关键参数的适当值实现了这四个变量的优化：分支程度和链的长度。这两个参数的最佳值恰恰就是在细胞糖原中发现的值。
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