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Published on: February 11, 2021
pH-Dependent structural change in neoculin with special reference to its taste-modifying activity
Yuji Morita1, Ken-ichiro Nakajima, Kisho Iizuka
1Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Bioscience, Biotechnology, and Biochemistry
|November 10, 2009
Summary
Neoculin
Area of Science:
- Biochemistry
- Molecular Biology
- Sensory Science
Background:
- Neoculin is a protein known for its taste-modifying properties.
- Its activity is suggested to be influenced by environmental factors like pH.
Purpose of the Study:
- To investigate the pH-dependent structural changes in neoculin.
- To elucidate the role of specific amino acid residues in neoculin's taste modification.
Main Methods:
- Spectroscopic analysis (fluorescence) of neoculin and its variants.
- Site-directed mutagenesis to alter histidine residues.
Main Results:
- Neoculin exhibited pH-dependent changes in tryptophan and ANS fluorescence spectra.
- A neoculin variant with altered histidine residues did not show these pH-dependent spectral changes.
- These findings indicate a link between structural conformation and pH.
Conclusions:
- The sweetness of neoculin is dependent on pH-induced structural alterations.
- Histidine residues are crucial for mediating these structural changes and neoculin's activity.
- Understanding these mechanisms can inform the development of novel taste modifiers.
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