Food Science and Technology Research
Online ISSN : 1881-3984
Print ISSN : 1344-6606
ISSN-L : 1344-6606
Original papers
High-yield Secretion of the Recombinant Sweet-Tasting Protein Thaumatin I
Tetsuya MASUDANobuyuki IDEKeisuke OHTANaofumi KITABATAKE
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2010 Volume 16 Issue 6 Pages 585-592


Thaumatin, an intensely sweet-tasting protein used as a sweetener, was secreted by the methylotrophic yeast Pichia pastoris. Approximately 100 mg L-1 of recombinant thaumatin I was obtained using an expression vector which possesses three copies of the thaumatin gene containing the 22-amino acid pre-sequence. Expression yield was about three-fold higher than when the α-factor secretion signal from Saccharomyces cerevisiae was used. The circular dichroism and tryptophan fluorescence spectra for recombinant thaumatin I were almost the same as those for plant thaumatin. Large amounts of homogeneous recombinant thaumatin allowed for preparation of high-quality crystals in the presence of cryoprotective glycerol used in high-resolution x-ray structural analysis to help further understand the perception of the sweet taste of thaumatin.

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© 2010 by Japanese Society for Food Science and Technology
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