1989 Fiscal Year Final Research Report Summary
Structure Determination and Development of Purification Process of Taste-modifying protein, Miraculin
| Project/Area Number |
62880021
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
代謝生物化学
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| Research Institution | Yokohama National University. Faculty of Education |
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Principal Investigator |
KURIHARA Yoshie Yokohama National Univ. Fac. of Education, Professor, 教育学部, 教授 (90017715)
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| Co-Investigator(Kenkyū-buntansha) |
KOIMAI Naoyoshi Mitajiri Chemical Industries, Ltd. Research and Development, Researcher, 研究員
NAKAYA Kazuyasu Showa University, School of Pharmaceutical Sciences, Assistant Professor, 薬学部, 助教授 (40053855)
NAKAMURA Yasuharu Showa University, School of Pharmaceutical Sciences, Professor, 薬学部, 教授 (70053759)
KURIHARA Kenzo Hokkaido Univ. Fac. of Pharmaceutical Sciences, Professor, 薬学部, 教授 (00016114)
ASOH Takeo Yokohama National Univ. Fac. of Education, Professor, 教育学部, 教授 (40017736)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Taste-modifiers / Taste-modifying protein / Asparagin-linked oligosaccharide / Miraculin / Miracle fruit / Glycoprotein / Anti-miraculin IgG |
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| Research Abstract |
1. The taste-modifying protein, miraculin, has the unusual property of modifying a sour taste into a sweet taste. We found that miraculin was extracted with 0.5 M NaCi solution. Miraculin was purified from the extracted solution by ammonium sulfate fractionation, CM-Sepharose ion-exchange chromatography, and gel-filtration. The purified miraculin thus obtained gave a single sharp peak in reverse phase high performance liquid chromatography, indicating that it is highly pure.
2. The complete amino acid sequence of miraculin was determined by an automatic Edman degradation method. Miraculin was a single polypeptide with 191 amino acid residues. The calculated molecular weight based on the amino acid sequence and the carbohydrate content was 24,600. The carbohydrate chains were elucidated to link to Asn-42 and Asn-186.
3. The structure of each N-linked oligosaccharides isolated was analyzed. It was found that five oligosaccharides are a series of compounds with xylose-containing common structural core. A variety of oligosaccharide structure are significant for two glycosylation sites, Asn-42 and Asn-186. Two new oligosaccharides with unusual structures containing complex-type were characterized.
4. We have developed an enzyme-linked lmmunoabsorbent assay for miraculin. The amounts of miraculin in miracle fruit increased dramatically seven weeks after pollination and reached a maximum at eight weeks. These results suggest that the biosynthesis of miraculin increases dramatically during the final stage of maturation of miracle fruit.
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