Construction of a recombinant thermostable β-amylase-trehalose synthase bifunctional enzyme for facilitating the conversion of starch to trehalose

Jia Hung Wang, Meng Yin Tsai, Guan Chiun Lee, Jei Fu Shaw*

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

34 引文 斯高帕斯(Scopus)

摘要

A fusion gene that encoded a polypeptide of 1495 amino acids was constructed from the β-amylase (BA) gene of Clostridium thermosulfurogenes and trehalose synthase (TS) gene of Thermus thermophilus. The fused gene was overexpressed in Escherichia coli, and a recombinant bifunctional fusion protein with BA at the N-terminal (BATS) or C-terminal (TSBA) of TS having both β-amylase and trehalose synthase activities with an apparent molecular mass of 164 kDa was obtained. BATS or TSBA catalyzes the sequential reaction in which maltose is formed from starch and then is converted into trehalose. The K m values of the BATS and TSBA fusion enzymes for the reaction from starch to trehalose were smaller than those of an equimolar mixture of BA and TS (BA/TS). On the other hand, the k cat value of BATS approximated that of the BA/TS mixture, but that of TSBA exceeded it. TSBA showed much higher sequential catalytic efficiency than the separately expressed BA/TS mixture. The catalytic efficiency of TSBA or BATS was 3.4 or 2.4 times higher, respectively, than that of a mixture of individual enzymes, showing the kinetic advantage of the fusion enzyme. The thermal stability readings of the recombinant fusion enzymes BATS and TSBA were better than that of the mixture of individual recombinant enzymes. These results apparently demonstrate that fusion enzymes catalyzing sequential reactions have kinetic advantages over a mixture of both enzymes.

原文英語
頁(從 - 到)1256-1263
頁數8
期刊Journal of Agricultural and Food Chemistry
55
發行號4
DOIs
出版狀態已發佈 - 2007 2月 21
對外發佈

ASJC Scopus subject areas

  • 一般化學
  • 一般農業與生物科學

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