The mobile polypeptide of Forster resonance energies

摘要

The purpose of the present invention is to provide a method for measuring the activity of a tyrosine kinase with high efficiency while reducing the number of cells which cannot be evaluated with respect to FRET. The problem can be solved by a polypeptide which is selected from polypeptides (1) and (2) as mentioned below and to which a donor and an acceptor for inducing Forster resonance energy transfer are bound: (1) a polypeptide which comprises an amino acid sequence that has the substitution of at least one amino acid residue selected from amino acid residues lying between position-91 to position-97 and/or at least one amino acid residue selected from amino acid residues lying between position-201 to position-222 in the amino acid sequence represented by SEQ ID NO: 2; and (2) a polypeptide which comprises an amino acid sequence that has the deletion of 1st to 81st amino acid residues as numbered from the carboxyl terminal side and also has the substitution of at least one amino acid residue selected from amino acid residues lying between position-91 to position-97 and/or at least one amino acid residue selected from amino acid residues lying between position-201 to position-222 in the amino acid sequence represented by SEQ ID NO: 2.