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Other quantitative proteomics services

Metabolic labeling is not always appropriate or is difficult to use for some quantitative proteomics analyses e.g. using human or animal tissues, patient samples, serum and primary differentiated cells that are not able to undergo multiple cell division cycles in culture.

DCP therefore, offers other quantitative proteomics services that enable the company to tailor the client’s proteomics needs to a strategy that uses the appropriate quantitative mass spectrometry tool for their project. We will discuss projects with clients and then determine the appropriate service that will provide a solution to their research and development problem.

Other quantitative proteomics services that we offer to clients include:

  • Isobaric Labeling: using tandem mass tags (TMT) or isobaric tags for relative and absolute quantitation (iTRAQ): These techniques involve the use of isobaric peptide labeling and quantitative mass spectrometry to analyse complex protein samples and tissues from patients or animal models where metabolic labeling techniques are not suitable.
  • Label-Free Quantitation: used in the global analysis and quantitation of differentially expressed proteins in complex proteomes. Label-free quantitative proteomics is suitable for samples that cannot be metabolically labeled e.g. patient samples, animal tissues and primary cells. The label-free approach provides a higher dynamic range of quantification and a simple biochemical workflow, which means that we can measure significant changes within a complex mixture or across an entire proteome in a single experiment depending on the complexity of the species' proteome. Another advantage of label-free quantitation is that many more different sample states can be compared in parallel than is possible with either metabolic or chemical labeling approaches.
  • Isotope-Coded Affinity Tag (ICAT): can be used to identify and quantify oxidation of cysteine thiols thus determination of the redox state of protein thiols. ICAT involves chemical labeling with probes that contain a reactive group that can be used in labeling a specific side in amino acids e.g. cysteine, an isotopically coded linker and an affinity tag for purification of tagged peptides and proteins. The purified peptides can be analysed by quantitative mass spectrometry.