Starch-biosynthesis enzymes producing the less stickiness of boiled rice of indica variety

淀粉生物合成酶降低籼米的粘性

基本信息

批准号：
07660171
负责人：
TAKEDA Yasuhito
金额：
$ 1.47万
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：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07660171/
关键词：
branching enzyme structure of amylopectin starch biosynthesis boiled rice indica rice japonica rice ジャポニカアミロペクチンの構造

项目摘要

Boiled rice of indica variety is less sticky compared with that of japonica variety, being suggested to be due to a higher amount of very long chains of indica amylopectin. Therefore, we examined branching enzyme from rice endosperm of indica and japonica varieties because the enzyme, out of enzymes involving starch biosynthesis, may have an important role to produce short and very long chains of amylopectin. Among six varieties examined here of indica and japonica rices, Saikai 184 variety had a typical type of indica amylopectin and Saikai 194 had that of japonica amylopectin having a small amount of very long chains. Immature endosperms (about 20 days after pollination) of Saikai 184 and Saikai 194 had at least two isoforms of branching enzyme with a various amount when examined by activity staining after gel electrophoresis. A major isoform was purified to be essentially free of amylase by chromatography on butyl-Toyopearl 650S,DEAE-Sepharose FF,Mono Q,Superose 12 and amylose-Sepharose 6B.Both preparations showed a similar ratio of the activities determined by the phosporylase stimulation assay and the branch linkage assay, and were found to transfer preferentially long chains when they were incubated with reduced amylose as a substrate. This type of chain transfer resembled that for maize BE-I isoform, but differed from that for maize BE-II isoform and for kidney bean enzyme which preferentially transferred short chains. However, the rice isoform and maize BE-I differed in producing a relatively high amount of chains with d. p. 10-12 and of a chain with d. p. 6, respectively. This result might imply that such an intrinsic chain transfer action determines chain-length distribution of amylopection in plant origin. The less stickiness of indica boiled rice might be clarified by further experiments on catalytic functions of starch synthase and /or minor isoform of branching enzyme.

与japonica品种相比，含义的米饭的粘性较少，这是由于含链链蛋白的链链含量较高。因此，我们检查了来自Indica和Japonica品种的水稻胚乳的分支酶，因为该酶从涉及淀粉生物合成的酶中可能具有重要作用来产生短而长的链淀粉链链。在此处检查的六个品种中，Saikai 184品种具有典型的indica amyleopectin类型，而Saikai 194具有少量长链的Japonica amyleopectin。 Saikai 184和Saikai 194的未成熟胚乳（大约20天后）至少有两个同工型分支酶，当通过凝胶电泳后的活性染色检查时，用不同的量具有不同的量。纯化的主要同工型被纯化为基本不含淀粉酶，这是丁酰基 - 摩托素650s，deae-sepharose ff，deae-sepharose ff，mono Q，somo q，superose 12和淀粉液 - 塞弗罗斯6B的制剂。均显示出相似的活性比例，当时是通过脉络脉络促进和分支链接的链接型脉络脉冲，并且是脉络脉络脉络的转移，并且它们是促进的链接，并且它们是促进的链接，并且是脉络脉络的链接，并且它们是促进的链接，并且是脉络脉络的链接，并且是脉络脉的转移时，它们是促进的，是脉络脉络的变化。作为基材。这种类型的链传递类似于玉米BE-I同工型，但与玉米BE-II同工型和肾豆酶有所不同，该酶优先转移了短链。但是，水稻同工型和玉米BE-I在产生d的链中相对较高的链中有所不同。 p。 10-12和带有d的链。 p。分别分别。该结果可能意味着这种固有的链传递作用决定了植物起源中链球化的链长分布。通过进一步实验淀粉合酶和 /或分支酶的次要同工型的催化功能，可以阐明Indica煮沸米的粘性。