Patent ID: 7674766
Filing Date: 2010-03-09
Classification: C07K,C12N,C12P,G01N

Abstract:
1. A method of separating peptides in a mixture of isolated C-terminally labeled peptides, comprising: a) providing a hydrosylate comprising a mixture of C-terminally labeled distinct peptides obtained by subjecting a plurality of C-terminally labeled distinct proteins to hydrolysis, wherein the label comprises an affinity marker, and wherein the C-terminally labeled distinct proteins are prepared by contacting a sample comprising a plurality of distinct proteins with the label and a transpeptidase that catalyzes the transfer of one molecule of the affinity marker to the C-terminus of the plurality of distinct proteins in the sample under conditions that favor the additive reaction over the exopeptidase reaction; b) contacting the hydrosylate with a ligand for the affinity marker so as to form a complex, thereby isolating the C-terminally labeled distinct peptides; c) disrupting the complex formed by the binding of the ligand to the affinity marker to yield purified C-terminally labeled distinct peptides; and d) separating the purified C-terminally labeled distinct peptides by mass spectrometry.