Factors determining starch function and molecular structure; how characteristic is enzymes of starch synthesis in plant origin

决定淀粉功能和分子结构的因素；

• 批准号: 10660130
• 负责人: TAKEDA Yasuhito
• 金额: $ 1.98万
• 依托单位: Kagoshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660130/
• 关键词: starch; amylose; amylopectin; granule bound starch synthesis; amylose content; branching enzyme; barley; 澱粉粒結合型澱粉合成酵素; GBSS; 澱粉生合成酵素

In order to find out the determining factor of starch characteristic in plant origin, we examined 1) molecular structure and function of high-amylose starches, 2) the relation between amount of granule bound starch synthase (GBSS) and amylose content and 3) the relation between function of branching enzyme (BE) and amylopectin structure. The results obtained suggested that GBSS and BE played an important role in characterization of starch.1. We found that starches from two high-amylose cultivars of barley had similar molecular structures of amylose and amylopectin to a normal cultivar of barley, and were actually high-amylose, differing from in the case of indicia rice, and gelatinized with very difficulty.2. We determined GBSS amount of starches from barley (4 cultivars), rice (12 cultivars), wheat (6 cultivars), maize (2 cultivars) and potato (5 cultivars) by SDS-PAGE, and found the following relations on GBSS amount. (1) Two types of plants were found in terms of the relation between GBSS amount and actual amylose content. One type of plant was barley and maize in which amylose content increased with increase of GBSS amount. The other type was rice, wheat and potato in which amylose content was constant even with increase of GBSS amount. (2) Rice GBSS, which synthesizes amylose, might also elongate a part of amylopectin chains and produce amylose-like very long chains.3. BE was purified from barley endosperm (23 days later flowering). There were two isoforms (BE I and BE II), which had different function in chain transfer, and the main isoform, BE I, was suggested to determine short-chain distribution of amylopectin.

为了找出植物起源中淀粉特征的确定因素，我们检查了1）高淀粉淀粉的分子结构和功能，2）颗粒结合淀粉合酶（GBSS）（GBSS）和淀粉酶含量和3）分支酶（BE）（BE）和氨基甲基胶质结构之间的关系之间的关系。获得的结果表明，GBSS并在淀粉的表征中起重要作用。我们发现，来自两个高淀粉质品种大麦品种的淀粉具有与正常大麦品种相似的分子结构，实际上是高淀粉酶，与米米的情况不同，并且含量很难。2。我们确定了来自大麦（4种品种），大米（12种品种），小麦（6种品种），玉米（2种品种）和马铃薯（5个品种）的GBS量，并通过SDS-PAGE确定了以下关系。 （1）根据GBSS量与实际链淀粉含量之间的关系发现了两种类型的植物。一种类型的植物是大麦和玉米，其中双淀粉含量随着GBS的增加而增加。另一种类型是大米，小麦和马铃薯，即即使增加了GBSS的含量增加，淀粉糖含量也是恒定的。 （2）合成链淀粉的水稻GBS也可能会拉长一部分链淀粉链链并产生类似链淀粉的非常长的链3。从大麦胚乳（23天后开花）中纯化。有两个同工型（是I和II），它们在链转移中具有不同的功能，并且建议主要的同工型确定淀粉蛋白酶的短链分布。