啤酒大麦β-淀粉酶热稳定性研究进展  

Advance in Study on Beta-amylase Thermostability in Malting Barley

作　　者：齐军仓[1] 张国平[1] 

机构地区：[1]浙江大学农学系

出　　处：《麦类作物学报》2005年第5期125-128,共4页Journal of Triticeae Crops

基　　金：国家自然科学基金项目(30270779);高等学校博士学科点专项科研基金项目(20020335028)

摘　　要：β-淀粉酶是与糖化力关系最为密切的淀粉水解酶,直接关系到麦芽生产的经济收益,而该酶的热稳定性影响制作过程中麦芽活力的表现。不同来源的大麦基因型在β-淀粉酶的热稳定性上存在着明显的差异,可以分为三种类型,呈一定的地理分布;遗传研究表明,β-淀粉酶的热稳定性受其结构基因位点和附近的复等位基因的共同控制,并受一些基因的修饰,不同热稳定性β-淀粉酶类型的形成是相关蛋白质顺序上少数氨基酸变化的结果。已经鉴定到控制大麦籽粒β-淀粉酶的三个基因Sd 1、Sd 2和Sd 3,它们分别控制着三种热稳定性类型。β-淀粉酶热稳定性显著影响麦芽汁发酵率,热稳定性等位基因不同的大麦,它们的麦芽汁发酵率也不同。通过构建β-淀粉酶热稳定性突变基因,并采用转基因技术导入该基因,可以显著提高大麦的β-淀粉酶热稳定性。最后就开展β-淀粉酶热稳定性的遗传和环境变异研究的意义进行了讨论。β-amylase was a starch-decomposing enzyme closely related to diastatic power during barley malting, influencing the economy of malt industry. It＇s thermostability affected the enzyme activity during malting. There was great difference in β-amylase thermostability of barley genotypes from the different areas, and three types may be classified according to the capacity of thermostability with a clear cultivar geographic distribution. The genetic research showed that β-amylase thermostability was co-dominated by structural gene locus and adjacent multiple alleles, and modified by some minor genes. The different β-amylases in thermostability were formed with the change of amino acids on the protein sequence. Three allele genes, namely Sd1, Sd2 and Sd3, encoding three β-amylase forms, have been identified respectively. β-amylase thermostability affected wort fermentability, and there was an obvious difference in wort fermentability among the barley cultivars with different alleles controlling thermostability. It was indicated that β-amylase thermostability could be enhanced through transferring the constructed mutant genes of β-amylase thermostability. The significance of investigation on genotypic and environmental variation in β-amylase thermostability was also discussed in the paper.

关 键 词：啤酒大麦 Β-淀粉酶 热稳定性 

分 类 号：S512.31[农业科学—作物学] S312