Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Biochem J. 2012 Feb 1;441(3):763-87. doi: 10.1042/BJ20111416.
Glycogen is a branched polymer of glucose that acts as a store of energy in times of nutritional sufficiency for utilization in times of need. Its metabolism has been the subject of extensive investigation and much is known about its regulation by hormones such as insulin, glucagon and adrenaline (epinephrine). There has been debate over the relative importance of allosteric compared with covalent control of the key biosynthetic enzyme, glycogen synthase, as well as the relative importance of glucose entry into cells compared with glycogen synthase regulation in determining glycogen accumulation. Significant new developments in eukaryotic glycogen metabolism over the last decade or so include: (i) three-dimensional structures of the biosynthetic enzymes glycogenin and glycogen synthase, with associated implications for mechanism and control; (ii) analyses of several genetically engineered mice with altered glycogen metabolism that shed light on the mechanism of control; (iii) greater appreciation of the spatial aspects of glycogen metabolism, including more focus on the lysosomal degradation of glycogen; and (iv) glycogen phosphorylation and advances in the study of Lafora disease, which is emerging as a glycogen storage disease.
糖原是葡萄糖的支链聚合物，在营养充足时作为能量储存，以备不时之需。其代谢已成为广泛研究的主题，并且人们对其受胰岛素、胰高血糖素和肾上腺素（肾上腺素）等激素的调节有了很多了解。关于关键生物合成酶糖原合酶的变构控制与共价控制的相对重要性，以及葡萄糖进入细胞与糖原合酶调节在决定糖原积累中的相对重要性，一直存在争议。过去十年左右，真核生物糖原代谢的重要新进展包括：（i）生物合成酶糖原合酶和糖原合酶的三维结构，以及对机制和控制的相关影响；（ii）对几种具有改变的糖原代谢的基因工程小鼠的分析，阐明了控制机制；（iii）对糖原代谢的空间方面有了更深入的了解，包括更加关注溶酶体对糖原的降解；以及（iv）糖原磷酸化和研究 Lafora 病的进展，Lafora 病正在成为一种糖原贮积病。
