Vessels J M, Radding J A
Department of Infectious Disease Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285.
Anal Biochem. 1993 Nov 15;215(1):150-5. doi: 10.1006/abio.1993.1567.
Crude membrane preparations of fungi contain the enzyme glucan synthase (EC 2.4.1.34) which produces a polymer of glucose linked through 1,3-beta-glycosidic bonds. This polymer is a major structural element of the fungal cell wall. Preparations of glucan synthase are contaminated with the enzyme glycogen synthase (EC 2.4.1.11). Glycogen synthase forms the storage carbohydrate glycogen, a polymer of glucose consisting of mainly 1,4-alpha-glycosidic linkage. Both enzymes utilize uridine diphosphoglucose as substrate. Discrimination of glucan synthase from glycogen synthase activity has relied upon the inclusion of glycogen-degrading enzymes in the crude reactions. The polysaccharide reaction products of glucan synthase assays have been characterized by their susceptibility to enzymatic degradation by various glucanohydrolases. These degradative enzymes are impure and inclusion of appropriate control polysaccharides often leads to ambiguous results. A method for comparative qualitative analysis of polysaccharides formed in fungal glucan synthase reactions has been developed using high-performance anion-exchange chromatography. Using this method, polymers of glucose with 1,3-beta-glycosidic linkage and 1,4-alpha linkage can be readily distinguished. This method has been applied to map oligosaccharides derived by partial acid hydrolysis from fungal glucan synthase reaction products from Candida albicans protoplasts prepared by two different methods.
真菌的粗制膜制剂含有葡聚糖合酶（EC 2.4.1.34），该酶可产生通过1,3-β-糖苷键连接的葡萄糖聚合物。这种聚合物是真菌细胞壁的主要结构成分。葡聚糖合酶制剂被糖原合酶（EC 2.4.1.11）污染。糖原合酶形成储存碳水化合物糖原，这是一种主要由1,4-α-糖苷键组成的葡萄糖聚合物。两种酶都利用尿苷二磷酸葡萄糖作为底物。区分葡聚糖合酶和糖原合酶活性依赖于在粗反应中加入糖原降解酶。葡聚糖合酶测定的多糖反应产物已通过它们对各种葡聚糖水解酶的酶促降解敏感性来表征。这些降解酶不纯，加入适当的对照多糖往往会导致结果不明确。已开发出一种使用高效阴离子交换色谱法对真菌葡聚糖合酶反应中形成的多糖进行比较定性分析的方法。使用这种方法，可以很容易地区分具有1,3-β-糖苷键和1,4-α-键的葡萄糖聚合物。该方法已应用于绘制通过部分酸水解从两种不同方法制备的白色念珠菌原生质体的真菌葡聚糖合酶反应产物中得到的寡糖图谱。
