EXAMINATION OF AMINO ACID SEQUENCE CONSTITUTING PEPTIDE DEPENDING ON ISOTOPIC RATIO

摘要

In determining and identifying an amino acid sequence of a peptide by using MS, it is intended to obtain additional data from MS for evaluating the adequacy of an amino acid sequence in a candidate list output from an identifying engine. Namely, a method of examining a deduced amino acid sequence for examining an amino acid sequence which has been deduced by searching for peptide data base based on peptide mass data and/or peptide modification data obtained by mass spectroscopy of the peptide, comprising: (1) the step of calculating the theoretical isotopic ratio of the peptide based on the deduced amino acid sequence and/or peptide modification data; (2) the step of measuring the isotopic ratio of the peptide based on the mass data of the peptide; and (3) the step of comparing the theoretical value with the measured value and evaluating the adequacy of the deduced amino acid sequence based on the difference between the theoretical value with the measured value.