Patent ID: 6629040
Filing Date: 2003-09-30
Classification: C12Q,G01N

Abstract:
A method for identifying a peptide or protein in a mixture comprising one or more peptides or proteins which comprises the steps of:(a) labeling one or more peptides or proteins in the mixture with a first isotope-distribution tag reagent which comprises an element having an isotope distribution not normally found in the one or more peptides or proteins in the mixture and which selectively reacts and bonds to a functional group in one or more peptides or proteins in the mixture to give one or more labeled peptides or proteins; (b) digesting the labeled peptides or proteins in the mixture using a digestion method that is selected to generate one or more digested peptides or proteins from the labeled peptides or proteins in the mixture that are selectively labeled with the first isotope-distribution tag reagent; (c) measuring the masses of the digested peptides or proteins selectively labeled with the first isotope-distribution tag reagent employing mass spectrometry to give the masses of digested peptides or proteins selectively labeled with the first isotope-distribution tag reagent; and (d) comparing the mass of one and only one single labeled digested peptide or protein determined in step (c) with one or more databases comprising the masses of peptides or proteins generated by digestion of known peptides or proteins using the digestion method of step (b) to identify the peptide or protein in the database from which the single digested peptide or protein is derived and to thereby identify one of the peptides or proteins in the mixture.