Defructosylation method
The present invention is directed to a defructosylation enzyme originating from a plant, a method of defructosylating a fructosylated peptide or protein through use of the enzyme, and a method of measuring a fructosylated peptide or protein.
1. A method for removing fructosyl group from an isolated fructosylated peptide or a fructosylated protein, comprising:
reacting the fructosylated peptide or protein with a aqueous extract from Pyrus pyrifolia, Vitis vinifera, or Daucus carota containing an enzyme that removes a fructosyl group from a peptide or polypeptide without removing an amino acid residue of said peptide or polypeptide.
2. The method of claim 1 , wherein said aqueous extract is from Pyrus pyrifolia.
3. The method of claim 1 , wherein said aqueous extract is from Vitis vinifera.
4. The method of claim 1 , wherein said aqueous extract is from Daucus carota.
5. The method of claim 1 , wherein said enzyme removes an N-terminal fructosyl group from a fructosylated peptide or fructosylated protein comprising Val-His (SEQ ID NO: 1).
6. The method of claim 1 , wherein said enzyme removes an N-terminal fructosyl group from a fructosylated peptide or fructosylated protein comprising Val-His-Leu (SEQ ID NO: 2).
7. The method of claim 1 , wherein said enzyme removes an N-terminal fructosyl group from a fructosylated peptide or fructosylated protein comprising Val-His-Leu-Thr (SEQ ID NO: 3).
8. The method of claim 1 , wherein said enzyme removes an N-terminal fructosyl group from a fructosylated peptide or fructosylated protein comprising Val-His-Leu-Thr-Pro (SEQ ID NO: 4).
9. The method of claim 1 , wherein said enzyme removes an N-terminal fructosyl group from a fructosylated peptide or fructosylated protein comprising Val-His-Leu-Thr-Pro-Glu (SEQ ID NO: 5).
10. The method of claim 1 , wherein the fructosylated protein is hemoglobin Alc.
11. The method of claim 1 , further comprising detecting at least one reaction product of removal of a fructosyl group from said fructosylated peptide or fructosylated protein.
12. The method of claim 11 , comprising detecting the reaction product hydrogen peroxide.
13. The method of claim 11 , comprising detecting the reaction product glucosone.
14. The method of claim 11 , comprising detecting the reaction product glucose.
15. The method of claim 11 , comprising detecting the reaction product defructosyl peptide.