胚乳中淀粉的合成

Starch Synthesis in Endosperm

禾本科植物胚乳内所含有的淀粉根据其结构、组成可以分为两类:直链淀粉(由α-1,4糖苷键连接的多聚D-葡萄糖)和支链淀粉(在以α-1,4糖苷键连接的主链上通过形成α-1,6糖苷键引入支链的多聚D-葡萄糖)。前者是以一种线性无序状态存在,而支链淀粉则是构成淀粉半晶体结构的主要成分。其中,除了负责合成作为糖基直接供体的ADP-Glc的酶AGPase外,直链淀粉中链的延伸反应由GBSSI完成,而支链淀粉的合成则相对复杂,需要SS、SBE、DBE、SP等一些酶的协同调控来共同完成。本文综述了胚乳中淀粉合成过程中所涉及的一些关键酶的研究进展,并对此研究领域进行了展望。

Starch is made up of amylose （linear α-1,4 polyglucans） and amylopectin （polyglucans linked together mainly by α-1,4 linkages but with 5%-6% of （α-1,6） bonds at the branch points）. Amylose exists as a linear and random form but amylopectin is the main component of starch semi-crystal structure. Except for AG- Pase which charges for the synthesis of ADP-Glc （the glucose direct donor）, the synthesis of amylose is under GBSSI＇s control. But for amylopectin synthesis, more enzymes are involved in, such as SS, SBE, DBE, SP etc. In this paper, we reviewed the research development on enzymes involved in starch synthesis pathway, and what＇s more, we give our view on the research prospect in this field.