Department of Microbiology, Pusan National University, Busan, Korea.
J Appl Microbiol. 2009 Oct;107(4):1119-30. doi: 10.1111/j.1365-2672.2009.04295.x. Epub 2009 Mar 30.
Isomaltulose (palatinose) is a slowly digestible sucrose isomer that can reduce both the glycemic and insulinemic response to foods. The aim of this study was to clone and express a sucrose isomerase (SIase) gene and characterize the protein that is responsible for the production of isomaltulose in the micro-organism Enterobacter sp. FMB-1.
A cosmid clone containing c. 6 kbp region encoding an SIase gene was identified. The 5969-bp chromosomal DNA fragment covering the SIase (esi) gene in Enterobacter sp. FMB-1 was sequenced. Although this DNA fragment contained several open reading frames other than esi, only the presence of esi was sufficient to produce isomaltulose in recombinant Escherichia coli. The esi gene was expressed in E. coli, leading to the characterization of its SIase activity.
The Enterobacter sp. FMB-1 esi gene was successfully cloned and expressed in E. coli. This gene encoded a functional SIase that produced isomaltulose from sucrose.
This is the first molecular analysis of an SIase gene in an Enterobacter strain. The functional expression of the Enterobacter sp. FMB-1 esi gene in E. coli offers an alternative choice for the industrial production of isomaltulose.
异麦芽酮糖(帕拉金糖)是一种缓慢消化的蔗糖异构体,可降低食物的血糖和胰岛素反应。本研究的目的是克隆和表达一种蔗糖异构酶(SIase)基因,并鉴定负责产生微生物肠杆菌 FMB-1 中异麦芽酮糖的蛋白质。
鉴定出一个含有编码 SIase 基因的约 6 kbp 区域的 cosmid 克隆。测序了肠杆菌 FMB-1 中包含 esi 基因的 5969-bp 染色体 DNA 片段。尽管该 DNA 片段包含 esi 以外的几个开放阅读框,但只有 esi 的存在足以在重组大肠杆菌中产生异麦芽酮糖。esi 基因在大肠杆菌中表达,导致其 SIase 活性得到了表征。
成功地从肠杆菌 FMB-1 中克隆并表达了 esi 基因。该基因编码一种功能性 SIase,可将蔗糖转化为异麦芽酮糖。
这是首次对肠杆菌属菌株中的 SIase 基因进行分子分析。在大肠杆菌中功能性表达肠杆菌属 FMB-1 的 esi 基因,为异麦芽酮糖的工业生产提供了另一种选择。