Complete purification and characterization of the taste-modifying protein, miraculin, from miracle fruit

J Biol Chem. 1988 Aug 15;263(23):11536-9.


The taste-modifying protein, miraculin, has the unusual property of modifying a sour taste into a sweet taste. Previous attempts to isolate miraculin from deeply colored alkaline extracts of the miracle fruit were unsuccessful. We found that miraculin is extracted with 0.5 M NaCl solution. The extracted solution is colorless and shows the strong sweet-inducing activity. Miraculin was purified from the extracted solution by ammonium sulfate fractionation, CM-Sepharose ion-exchange chromatography, and concanavalin A-Sepharose affinity chromatography. The purified miraculin thus obtained gave a single sharp peak in reverse phase high performance liquid chromatography, indicating that it is highly pure. The sample also gave a single band having molecular weight 28,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This value was much lower than the values reported previously (40,000-48,000). The amino acid composition of the purified miraculin was determined. Sequence analysis of the purified miraculin indicated that it is composed of a pure single polypeptide and identified 20 amino-terminal amino acids. The purified miraculin contained as much as 13.9% of sugars, which consisted of glucosamine, mannose, galactose, xylose, and fucose in a molar ratio of 3.03:3.00:0.69:0.96:2.12.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / analysis
  • Chromatography, High Pressure Liquid
  • Electrophoresis, Polyacrylamide Gel
  • Fruit / analysis*
  • Glycoproteins / isolation & purification*
  • Glycoproteins / metabolism
  • Molecular Weight
  • Sweetening Agents / isolation & purification*
  • Sweetening Agents / metabolism


  • Amino Acids
  • Glycoproteins
  • Sweetening Agents
  • miraculin protein, Synsepalum dulcificum