| 主权项 |
1. A method for the quantitative detection of a target protein in a sample, comprising the following steps:
a) treatment of the sample in order to generate peptides, b) quantitative assaying of at least one proteotypic peptide generated from the target protein, via a mass spectrometry technique implementing the following steps i) to vii):
i) ionizing of the proteotypic peptide to give precursor ions which are filtered according to their mass m/z, and selecting a given precursor ion having a mass (m/z)1 according to the target protein sought,ii) fragmenting of the selected precursor ion into first-generation fragment ions,iii) filtering the first-generation fragment ions generated according to their mass m/z, and selecting a given first-generation fragment ion having a mass (m/z)2 according to the target protein sought,iv) fragmenting the selected first-generation fragment ion into second-generation fragment ions,v) detecting of at least a part of the second-generation fragment ions so as to give a series of quantitative measurements,vi) selecting of at least one quantitative measurement associated with a second-generation ion, andvii) correlating the at least one selected quantitative measurement associated with the second-generation ion to the amount of proteotypic peptide generated and to the amount of target protein present in the sample, with the implementation of a calibration step, wherein said calibration step is performed using a calibration curve or internal calibration with a heavy peptide, wherein said selected quantitative measurement is performed by multiple reaction monitoring3 (MRM3), and wherein said selected first-generation fragment ion having a (m/z)2 is a doubly-charged peptide which has a proline or a histidine in position 1. |
