Customer Education

Stable Isotope-Labeled Protein Internal Standards Webinar

Duration: 75 minutes

 What Does it Cover?

Mass spectrometry-based protein assays impart increased specificity and more rapid development times versus traditional methods, such as ELISA. Coupled with immunoaffinity enrichment, LC-MS/MS is becoming a powerful tool for the quantitation of proteins in plasma. Such methods typically rely on synthetic stable isotope labeled (SIL) peptide internal standards to correct for instrumental variability. For more accurate protein quantitation by LC-MS/MS, experimental variations throughout the entire sample preparation workflow, including protein fractionation, immunoaffinity enrichment, and enzymatic digestion, must be accounted for. An ideal way of improving assay reproducibility is to add a full-length stable isotope labeled recombinant protein, that is equivalent to the native target protein, to the sample at the initial stage of the assay workflow. We have developed a set of stable-isotope-labeled monoclonal antibodies expressed in CHO cells as well as SIL versions of several clinically-relevant human proteins expressed in E. coli, such as IGF1, and in mammalian HEK293 cells, such as Thyroglobulin (manufactured as a Certified Reference Material). We will present data to demonstrate that the use of full-length SIL proteins and antibodies as internal standards allows for more accurate and rapid quantitation of biotherapeutic antibodies and clinically-relevant human protein biomarkers in plasma by LC-MS/MS.

For more information on our Thyroglobulin CRM, please reference our 2017 paper, published in the journal Analytical Chemistry.

 What Will You Learn?

  • Learn about Protein Reference standards for LC/MS applications
  • Simplifying the mass spectrometry workflow
  • Rapid and accurate quantitation of antibodies and proteins
Speaker Bio
James Walters, Ph.D.
Applied Analytical Technology Specialist
Jim Walters is an Applied Analytical Technology Specialist. This role was preceded by 10+ years as a Principal R&D Scientist in the Analytical R&D Department.

He received his Ph.D. at the University of South Carolina in 2000 from the Biomedical Science program in the Department of Microbiology and Immunology. He completed a post-doctoral research fellowship in Biomedical Mass Spectrometry at the Washington University Department of Chemistry in St. Louis, MO under Professor Michael Gross.

In 2006, Jim joined us in the Analytical R&D Department. Jim and his colleagues in Analytical R&D were on the fore front of a stable-isotope-labeled intact protein program for use as internal standards in quantitative proteomic workflows. Jim has over 19 years of experience applying liquid chromatography-mass spectrometry to biotechnology and proteomics, commercializing numerous products. In his current role, he supports Account Managers via interfacing with end-users to educate and inform, empowering them to select the best solutions for their analytical needs.