Patent ID: 8278115
Filing Date: 2012-10-02
Classification: G01N,H01J,Y10T

Abstract:
1. A method for determining a composition of a polypeptide, said method comprising: introducing said polypeptide to a mass spectrometer; selectively fragmenting said polypeptide to generate c and z-type product ions; providing a database of mass-to-charge values for possible c and z-type product ions from possible amino acid sequences; distinguishing said z-type product ions from said c-type product ions by measuring the mass-to-charge ratio of said z-type product ions and said c-type product ions at a mass accuracy better than or equal to 20 ppm sufficient to distinguish said z-type product ions from said c-type product ions, comparing the measured mass-to-charge ratio to said database of mass-to-charge values; assigning chemical compositions to a plurality of c and z-type product ions from said comparing step to obtain a chemical composition vector that describes a combination of amino acids from the N or C-terminus of said polypeptide; and determining said composition of said polypeptide by comparing said chemical composition vector to a polypeptide or protein database.