科研之友
微信
新浪微博
Facebook
分享链接
摘要
Interest in use of resistant starch and maltooligosaccharides as functional foods and biopreservatives has grown in recent years. In this research, a novel debranching enzyme IsoM from Corallococcus sp. strain EGB was identified and expressed in P. pastoris GS115. Sequence alignments showed that IsoM was typical isoamylase with the specific activity up to 70,600 U/mg, which belongs to glycoside hydrolase family 13 (GH 13). Enzymatic reaction pattern demonstrated that IsoM has high debranching efficiency against alpha-1,6-glycosidic bond of branched starch, and exhibited no activity towards alpha-1,4-glycosidic bond. The potential application of IsoM in starch processing was determined. IsoM was a potential candidate for the production of RS (70.9%) from raw starch, which was comparable with the commercial pullulanase (Promozyme (R) D2). IsoM also improved the maltohexaose yield in combination with maltohexaose-producing alpha-amylase AmyM (KM114206), the maltohexaose yield was improved by 63.3% compared with 21.9% improvement of Promozyme (R) D2. The results of RS production and combination with other amylases suggesting that IsoM is a potential candidate for the efficient conversion of starch.
