中文摘要：

多功能淀粉酶是α淀粉酶家族（α-amylase family）的新一类成员，包括新普鲁兰酶、麦芽糖淀粉酶和环麦芽糊精酶，它们在结构上具有α淀粉酶家族共有的4个高度保守的区域，但在功能上又兼有糖苷水解酶和糖基转移酶的催化活性，而不同的多功能淀粉酶虽然在结构与功能上具有一定的相似性，但不同来源的酶在底物特异性和水解、转移糖苷键的特异性等方面存在着差异．多功能淀粉酶大多存在单体与二聚体或多聚体之间的平衡，其多聚化与N结构域和环境中的离子强度调控有关．实验证明，通过突变可以改变多功能淀粉酶的催化特性，甚至仅1个氨基酸的替换就能实现功能改变．多功能淀粉酶的结构保守性和催化多样性具有重要的研究价值及应用前景．

英文摘要：

Multifunetional amylases including neopullulanase, mahogenic amylase and cyclomaltodextrinase have formed a new group of the α-amylase family. They possess the four high conserved regions of the α- amylase family in their primary sequence, which is known as the common structural element of the family, meanwhile they have dual activity of glycoside hydrolase and glycosyltransferase. On the other hand, although these muhifunetional amylases have similar structures and functions, they have different substrate and glycosidic bond specificities depending on their origin. In genernal, there is an equilibrium between their monomer and dimmer or polymer, and their N domain and the ionic strength in catalytic system likely to be responsible for their oligomerization or polymerization. Mutations, even though a single amino acid mutation, of these enzymes may lead to the change of their catalytic model. The structure conservatism and catalytic versatility of these muhifunetional amylases make them have both theoretical research meaning and practical applicative values.