Patent ID: 8889423

Claim:
A method for analyzing binding ability of plural kinds of proteins to a compound, comprising the steps of: (a) fractionating a first group containing plural kinds of isotope-labeled proteins into plural fractions using a chromatography column comprising a carrier having the compound immobilized thereon; (b) fractionating a second group containing plural kinds of proteins into one or plural fractions using a chromatography column comprising a carrier having the compound immobilized thereon; (c) adding a certain amount of the one fraction obtained in step (b), a certain amount of a mixture of all the fractions obtained in step (b) or a certain amount of a mixture of plural contiguous fractions among the fractions obtained in step (b), to each of the fractions obtained in step (a) so as to obtain combined fractions, wherein each of the combined fractions is maintained separately from other combined fractions; (d) analyzing separately each of the combined fractions obtained in step (c) with mass spectrometry to obtain mass spectrometry protein peaks; and (e) obtaining, regarding each combined fraction obtained in step (c), an intensity ratio between protein peaks of the first group and protein peaks of the second group based on the mass spectrometry analysis of step (d) to determine in which fraction each protein is concentrated, and determining that a protein concentrated in a fraction which is eluted later from the column has a higher binding ability to the compound than a protein concentrated in a fraction which is eluted earlier from the column among the plural kinds of proteins, thereby creating rankings of the binding ability of the proteins to the compound.