Abstract: The invention relates to a method for the determination of a cancer diagnostic/therapeutic biomarker assay and drug-targets including the following steps: (a) identification of potential candidate protein/peptide biomarkers and drug-targets based on the measurement of protein/peptide constituent concentrations in tissue sample proteomes as well as serum, plasma or any other derivatives of blood, or blood itself sample proteomes derived from healthy non-human mammalian individuals as well as from cancerous non-human mammalian individuals and qualitatively selecting as potential candidate protein/peptide biomarkers those which show a pronounced differential behaviour between healthy and cancerous sample proteomes; (b) optional verification of the potential candidate protein/peptide biomarkers as identified in step (a) by quantitative mass spectrometric measurement of the potential candidate protein biomarkers in serum, plasma or any other derivatives of blood, or blood itself sample proteomes derived from healt

Abstract: Methods of using halogenated peptides as internal standards for liquid chromatography-mass spectrometry, and novel halogenated peptides useful for the same, are disclosed. In particular, methods of using halogenated peptides as internal standards in proteomic analyses, as well as methods of using halogenated peptides to conduct quality control assessments of and/or to calibrate liquid chromatography-mass spectrometry systems are disclosed.

Abstract: The invention provides methods for generating an antibody specific for the deglycosylated form of a glycopolypeptide using a peptide corresponding to an N-linked glycosylation site of a glycopolypeptide. The invention additionally provides methods for generating an antibody specific for a glycopolypeptide using a peptide corresponding to amino acids adjacent to an authentic N-linked glycosylation site.

Abstract: The invention provides a method for identifying and quantifying polyglycopeptides in a sample. The method can include the steps of immobilizing glycopolypeptides to a solid support; cleaving the immobilized glycopolypeptides, thereby releasing non-glycosylated peptides and retaining immobilized glycopeptides; releasing the glycopeptides from the solid support; and analyzing the released glycopeptides. The method can further include the step of identifying one or more glycopeptides, for example, using mass spectrometry.

Abstract: The invention provides a method for identifying and quantifying polyglycopeptides in a sample. The method can include the steps of immobilizing glycopolypeptides to a solid support; cleaving the immobilized glycopolypeptides, thereby releasing non-glycosylated peptides and retaining immobilized glycopeptides; releasing the glycopeptides from the solid support; and analyzing the released glycopeptides. The method can further include the step of identifying one or more glycopeptides, for example, using mass spectrometry.

Abstract: The present invention is directed generally to tissue-derived glycoproteins and glycosites detectable in plasma via mass spectrometric analysis of glycoproteins from both tissues and blood. The invention also provides methods for identifying tissue-derived glycoproteins and glycosites in plasma, panels of detection reagents for detecting same, as well methods for detecting disease using such panels. The invention further provides a database of tissue-derived glycoproteins and glycosites detectable in plasma.

Abstract: The invention provides compositions and methods for identifying and/or quantifying glycopolypeptides from human serum or plasma. The compositions and methods include a plurality of standard peptides containing glycosylation sites determined for human serum/plasma proteins.

Abstract: The invention provides methods for identifying a polypeptide. The method can include determining two or more characteristics associated with the polypeptide, or a fragment thereof, one of the characteristics being mass of a fragment of the polypeptide, the fragment mass being determined by mass spectrometry; comparing the characteristics associated with the polypeptide to an annotated polypeptide index; and identifying one or more polypeptides in the annotated polypeptide index having the characteristics. The method can further include the steps of determining one or more additional characteristics associated with the polypeptide; comparing the determined characteristics to the annotated polypeptide index; optionally repeating the steps one or more times, wherein a set of characteristics is determined that identifies a single polypeptide in the annotated polypeptide index, and optionally quantitating the amount of identified polypeptide in a sample containing the polypeptide.

Abstract: Analytical reagents and mass spectrometry-based methods using these reagents for the rapid, and quantitative analysis of proteins or protein function in mixtures of proteins. The methods employ affinity labeled protein reactive reagents having three portions: an affinity label (A) covalently linked to a protein reactive group (PRG) through a linker group (L). The linker may be differentially isotopically labeled, e.g., by substitution of one or more atoms in the linker with a stable isotope thereof. These reagents allow for the selective isolation of peptide fragments or the products of reaction with a given protein (e.g., products of enzymatic reaction) from complex mixtures. The isolated peptide fragments or reaction products are characteristic of the presence of a protein or the presence of a protein function in those mixtures. Isolated peptides or reaction products are characterized by mass spectrometric (MS) techniques.

Abstract: The invention provides methods of detecting polypeptides in a sample. The method can include the steps of cleaving polypeptides in a test sample to generate peptides; adding a predetermined amount of isotopically labeled peptide standards to the cleaved test sample, wherein the peptide standards correspond to peptides cleaved with the same reagent used to cleave the test sample; contacting the cleaved test sample containing peptide standards with an array of immobilized binding agents specific for the peptide standards; washing the array to remove unbound peptides, thereby retaining affinity captured sample peptides and standard peptides; analyzing the affinity captured peptides using mass spectrometry; and determining the presence of bound test peptides and standard peptides. The method can further include the step of quantifying the amount of the test peptides by comparing the ratio of test peptide to corresponding standard peptide.