The Maltase Involved in Starch Metabolism in Barley Endosperm Is Encoded by a Single Gene.
The Maltase Involved in Starch Metabolism in Barley Endosperm Is Encoded by a Single Gene.
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DOI：
10.1371/journal.pone.0151642
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Smith AM
中科院分区：
文献类型：
--
作者：
Andriotis VM;Saalbach G;Waugh R;Field RA;Smith AM
在大麦萌发和幼苗早期生长过程中，麦芽糖酶负责将胚乳中淀粉降解产生的麦芽糖转化为葡萄糖以供幼苗生长。尽管这种酶与麦芽和酒精饮料的生产有潜在的相关性，但麦芽糖酶的性质和作用尚不完全清楚。虽然只有一个编码麦芽糖酶的基因被确定，但有证据表明存在其他基因和多种形式的麦芽糖酶。麦芽糖酶可能直接参与淀粉颗粒的降解，也可能参与麦芽糖的水解。我们工作的目的是为了发现大麦胚乳中麦芽糖酶的性质。用离子交换层析法从幼苗胚乳中分离麦芽糖酶活性，并对麦芽糖酶活性进行部分纯化，用于蛋白质鉴定。我们比较了野生型大麦和麦芽糖酶基因Agl97表达降低的转基因大麦的麦芽糖酶活性，并利用基因组和转录信息寻找更多的麦芽糖酶基因。我们发现大麦胚乳中的所有麦芽糖酶活性都可以由一个基因Agl97解释。多种形式的酶很可能来自蛋白分解和其他翻译后修饰。
During germination and early seedling growth of barley (Hordeum vulgare), maltase is responsible for the conversion of maltose produced by starch degradation in the endosperm to glucose for seedling growth. Despite the potential relevance of this enzyme for malting and the production of alcoholic beverages, neither the nature nor the role of maltase is fully understood. Although only one gene encoding maltase has been identified with certainty, there is evidence for the existence of other genes and for multiple forms of the enzyme. It has been proposed that maltase may be involved directly in starch granule degradation as well as in maltose hydrolysis. The aim of our work was to discover the nature of maltase in barley endosperm. We used ion exchange chromatography to fractionate maltase activity from endosperm of young seedlings, and we partially purified activity for protein identification. We compared maltase activity in wild-type barley and transgenic lines with reduced expression of the previously-characterised maltase gene Agl97, and we used genomic and transcriptomic information to search for further maltase genes. We show that all of the maltase activity in the barley endosperm can be accounted for by a single gene, Agl97. Multiple forms of the enzyme most likely arise from proteolysis and other post-translational modifications.