1991 Fiscal Year Final Research Report Summary
Structure Determination of a New Type of Taste-modifying Protein with Activity of Modifying a Sour Taste into Sweet Taste.
| Project/Area Number |
01480066
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
製造化学・食品
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| Research Institution | Yokohama National University |
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Principal Investigator |
KURIHARA Yoshie Yokohama Natl. Univ., Fac. of Education, Professor., 教育学部, 教授 (90017715)
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| Co-Investigator(Kenkyū-buntansha) |
NAGASE Shigeru Yokohama Natl. Univ., Fac. of Education, Professor, 教育学部, 教授 (30134901)
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| Project Period (FY) |
1989 – 1991
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| Keywords | curculin / sweet protein / taste-modifying protein |
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| Research Abstract |
A new taste-modifylng protein named curculin was extracted with 0.5 M NaCl solution from fruits of Curculiro atifolia and purified by ammonium sulfate fractionation, CM-Sepharose Ion-exchange chromatography, and gcl filtration. The purilied curculin thus obtained gave a single band having molecular welght of 12, 000 In sodium dodecyl sulfate-polyacrylamide gel electrophoresis In the presence of 8 M urea. The molecular weight determined by low-angle light scattcring was 27, 800. These results suggested that native curculin Is a dimer of 12, 000 dalton polypeptide. The complete amino acid sequence of curculin was determined by an automatic Edman degradation method. Curculin consists of 114 amino acid residues. Curculin itself elicits a sweet taste. After curculin, water elicits a sweet taste and sour substances induce stronger sweetness. No protein carrying both a sweet-tasting activity and taste-modifying activitics has ever been known. There were 5 sets of tripeptides common to miraculin (taste-modifying protein). 6 sets of tripeptides common to thaumatln (sweet protein) and 2 sets of tripeptides common to monellin (sweet protein). An enzymc immunoassay method for curculin was established. This method can accurately quantity 0.05-20 ng of curculin, sensitivity about 3000-times that of the psychometric method. Immunoblot analysis Indicated that antiserum to curculin was faintly reactive with miraculin, but not with thaumatin or moncllin. The mechanism of the taste-modifying actions of curculin were discussed.
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