不同淀粉组分含量小麦品种灌浆过程中淀粉去分支酶的活性及类型

【目的】研究不同淀粉组分含量小麦品种灌浆过程中籽粒所含淀粉去分支酶的活性及类型,为研究其在小麦支链淀粉合成中的作用提供理论依据。【方法】利用非变性PAGE与HPLC技术,对糯麦1号、关东107、鲁麦21和济南16四个小麦品种灌浆过程中的淀粉去分支酶进行分析。【结果】在灌浆过程中,淀粉去分支酶的活性均呈单峰曲线变化,灌浆中期活性最大;淀粉去分支酶对底物支链淀粉均具有相似的酶解活性;对灌浆中期小麦淀粉去分支酶进行的纯化结果表明,小麦籽粒胚乳中也存在2种类型的淀粉去分支酶,一种是以极限糊精为特异性底物的极限糊精酶(Limit dextrinase),另一种是以支链淀粉为底物的异淀粉酶(Isoamylase)。【结论】虽然小麦淀粉组分含量不同,但所含的淀粉去分支酶却具有相似的活性变化,在体外对底物——支链淀粉也有相似的酶解活性。

Activity and Types of Starch Debranching Enzyme in Wheat Cultivars Containing Different Starch Contents During the Grain Filling Period

[Objective]In order to provide a theoretical basis on studying the mechanism of starch debranching enzyme(DBE)further, activity differences and type of DBE during grain filling period of four wheat cultivars were studied.[Method] Activity differences and type of DBE among Nuomai I, Guandong 107, Jinan 16, and Lumai 21 were analyzed using native-PAGE and HPLC techniques.[Result]Changes of DBE activity of four cultivars had a single-peak curve, and the peak appeared in 14 d after anthesis.HPLC analysis showed that the activity of DBE to amylopectin was similar.There are two types of DBE in the wheat grains, one is isoamylase, and the other is limit dextrinase.[Conclusion]Though starch constitution of four cultivars is different, the DBE activity has a similar activity change of single-peak curve and the activity to amylopectin is similar in vitro.