糖原合成
中文名称
通路描述
糖原是一种高度分支的葡萄糖聚合物，在大多数人体组织中形成和分解，但在肝脏和肌肉中最为丰富，其中作为主要储存燃料。糖原代谢在肌肉中研究最为详尽，尽管关于肝脏中这些反应的实验数据相当丰富。其他组织的糖原代谢研究较少，被认为类似于肌肉过程。糖原合成涉及五个反应。前两个反应（葡萄糖6-磷酸转化为葡萄糖1-磷酸以及葡萄糖1-磷酸和UTP合成UDP-葡萄糖）与几种其他途径共享。接下来的三个反应（在糖原原蛋白上催化合成的葡萄糖寡聚体的自催化合成、由糖原合酶催化葡萄糖寡聚体的线性延伸以及由糖原分支酶催化分支的形成）是糖原合成所特有的。重复最后两个反应生成大且高度分支的糖原聚合物。肝细胞和非肝组织中由不同同工酶催化糖原原蛋白的葡萄糖化和寡糖链延伸，使得它们能够独立调节（Agius 2008; Bollen et al. 1998; Roach et al. 2012）。
英文描述
Glycogen synthesis Glycogen, a highly branched glucose polymer, is formed and broken down in most human tissues, but is most abundant in liver and muscle, where it serves as a major stored fuel. Glycogen metabolism has been studied in most detail in muscle, although considerable experimental data are available concerning these reactions in liver as well. Glycogen metabolism in other tissues has not been studied as extensively, and is thought to resemble the muscle process. Glycogen synthesis involves five reactions. The first two, conversion of glucose 6-phosphate to glucose 1-phosphate and synthesis of UDP-glucose from glucose 1-phosphate and UTP, are shared with several other pathways. The next three reactions, the auto-catalyzed synthesis of a glucose oligomer on glycogenin, the linear extension of the glucose oligomer catalyzed by glycogen synthase, and the formation of branches catalyzed by glycogen branching enzyme, are unique to glycogen synthesis. Repetition of the last two reactions generates large, extensively branched glycogen polymers. The catalysis of glycogenin glucosylation and oligoglucose chain extension by distinct isozymes in liver and nonhepatic tissues allows them to be regulated independently (Agius 2008; Bollen et al. 1998; Roach et al. 2012).
所含基因
14 个基因