Patent ID: 9163276
Filing Date: 2015-10-20
Classification: C12Q,G01N

Abstract:
1. A method for producing a stable isotope-labeled target peptide fragment in mass spectrometry, comprising the following steps (a) to (d): (a) expressing a DNA conjugate in a system having a stable isotope-labeled amino acid to thereby prepare a stable isotope-labeled protein, wherein the DNA conjugate comprises: wherein the peptide fragments for concentration measurement are different in amino acid sequence from naturally occurring proteins and their variants, and detectable by a liquid chromatograph-tandem mass spectrometer (LC/MS/MS); (b) subjecting the stable isotope-labeled protein to digestion by trypsin to prepare stable isotope-labeled peptide fragments for concentration measurement and stable isotope-labeled target peptide fragments; (c) quantifying the stable isotope-labeled peptide fragments for concentration measurement using LC/MS/MS; and (d) calculating the concentration of the stable isotope-labeled target peptide fragments from the quantification value of the stable isotope-labeled peptide fragments for concentration measurement.