33 results about "Peptide analysis" patented technology

A method of analyzing a liquid mixture comprising protein or peptide molecules mixed with other molecules comprises: passing a portion of the mixture through a liquid chromatograph so as to elute the molecules; transferring the eluted portions of the molecules to an ion source of a mass spectrometer so as to generate ions comprising a plurality of ion species therefrom; transferring the generated ion species to a mass analyzer for detection thereby; generating a respective record of the intensity-versus-time variation of each of a plurality of the detected ion species; identifying and distinguishing a set of ion species corresponding to the ions generated from the eluted portion of the protein or peptide analyte molecules based on the records of the intensity-versus-time variation; and performing at least one additional operation on ions of one or more of the distinguished ion species generated from the protein or peptide analyte molecules.

In large scale proteome applications, protein separation is paramount to observing discrete changes and quantitative evaluation must coincide with qualitative protein identification for effective differential analysis. A four dimensional (4D) platform for resolving and differentially analyzing complex biological samples is presented. The system, collectively termed CAX-PAGE / RPLC-MSMS, combines bi-phasic ion-exchange chromatography (1st dimension) and polyacrylamide gel electrophoresis (2nd dimension) for protein separation, quantification and differential band targeting leading toward subsequent capillary reverse phase liquid chromatography (3rd dimension) and data dependant tandem mass spectrometry (4th dimension) for semi-quantitative and qualitative peptide analysis.

The present invention provides a compound that can utilize hydrogen isotope and, at the same time, can quantify multiplexed samples at one time, as well as decreasing the cost for synthesis of the labeling agent. In addition, the present invention provides a novel method for quantitatively analyzing protein and peptide analytes having different quantities form each other using the labeling agent, wherein y-type fragment ions having a high mass which comprises the analyte remained after coupling the labeling agent with the analyte and then removing a part of the labeling agent through tandem mass spectrometry are utilized to conduct the quantitative analysis.

The invention provides methods for isolating a modified peptide from a complex mixture of peptides, the method comprising the steps of: (a) obtaining a proteinaceous preparation from an organism, wherein the preparation comprises modified peptides from two or more different proteins; (b) contacting the preparation with at least one immobilized modification-specific antibody; and (c) isolating at least one modified peptide specifically bound by the immobilized modification-specific antibody in step (b). The method may further comprise the step of (d) characterizing the modified peptide isolated in step (c) by mass spectrometry (MS), tandem mass spectrometry (MS-MS), and / or MS3 analysis, or the step of (e) utilizing a search program to substantially match the spectra obtained for the modified peptide during the characterization of step (d) with the spectra for a known peptide sequence, thereby identifying the parent protein(s) of the modified peptide. Also provided are an immunoaffinity isolation device comprising a modification-specific antibody, and antibodies against novel UFD1 and PTN6 phosphorylation sites.

The invention discloses a method for rapidly analyzing protein and strong-polarity long amino acid sequence glycopeptides in a biological sample. The method comprises the following steps of preparingsample protein; preparing a mixed chromatographic column through a one-step enrichment method: mixing C18 and MAX filler to prepare the mixed chromatographic column; carrying out protein digesting; carrying out glycopeptides enriching: enriching glycopeptides by using the mixed chromatographic column; and carrying out LC-MS / MS analysis. According to the one-step enrichment method disclosed by theinvention, the enrichment and identification efficiencies of the glycopeptides with long sequence and stronger polarity are very high; and compared with a traditional sample preparation method, the method disclosed in the invention requires less sample preparation process and time, and only requires less than one hour of the preparation time before mass spectrometry analysis.

The present disclosure provides a method and apparatus for improvements of sample throughput in proteome analysis by mass spectrometry, by combining multiple non-overlapping isoelectric focusing separations. The method for performing an analysis of a plurality of protein samples, comprises: (a) Adding a proteolytic enzyme of a given specificity to a first protein sample to digest proteins to peptides; (b) Separating the peptides obtained in step (a) by isoelectric focusing; (c) Collecting those peptides which have their isoelectric point value within a first isoelectric point range; (d) Adding a proteolytic enzyme of a given specificity to a second protein sample to digest proteins to peptides; (e) Separating the peptides obtained in step (d) by isoelectric focusing; (f) Collecting those peptides which have their isoelectric point value within a second isoelectric point range, where said second isoelectric point range is different and non-overlapping compared to said first isoelectric point range; (g) Combining the peptides collected in steps (c) and (f) into a single sample and subjecting said sample to mass spectrometry analysis; (h) Deconvoluting signals / data obtained from the mass spectrometry analysis by calculating the isoelectric point of each peptide, and assigning a peptide to the first protein sample if its isoelectric point value matches the isoelectric point range selected in step (c) or to the second protein sample if its isoelectric point value matches the isoelectric point range selected in step (f); and (i) Obtaining quantitative information for proteins of each sample according to magnitude of the signal obtained from each peptide.