Wilson Wayne A, Hughes William E, Tomamichel Wendy, Roach Peter J
Department of Biochemistry and Molecular Biology, Center for Diabetes Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Biochem Biophys Res Commun. 2004 Jul 23;320(2):416-23. doi: 10.1016/j.bbrc.2004.05.180.
Glycogen is a branched polymer of glucose, synthesized as a reserve of both energy and carbon. The branched nature of glycogen is important for its function and polyglucosan bodies, particles that contain a glycogen-like polymer with reduced branching, are a feature of several disease states. The degree of glycogen branching is thought to be governed by the balance between glycogen synthesis and branching activities. However, there have been reports that the intrinsic properties of individual branching enzymes govern the degree of branching. To address the relationship between synthesis and branching more fully, we made use of the yeast Saccharomyces cerevisiae. The glycogen content of yeast cells was manipulated by using different growth conditions or by the introduction of specific mutations. Whenever glycogen storage was elevated, the polysaccharide formed was found to be less branched but normal branching could be restored by overexpression of branching enzyme.
糖原是葡萄糖的分支聚合物，作为能量和碳的储备而合成。糖原的分支性质对其功能很重要，而多聚葡萄糖体是含有分支减少的类糖原聚合物的颗粒，是几种疾病状态的特征。糖原分支程度被认为受糖原合成与分支活性之间平衡的控制。然而，有报道称个别分支酶的内在特性决定分支程度。为了更全面地研究合成与分支之间的关系，我们利用了酿酒酵母。通过使用不同的生长条件或引入特定突变来控制酵母细胞的糖原含量。每当糖原储存增加时，发现形成的多糖分支较少，但通过分支酶的过表达可以恢复正常分支。
