Selected Reaction Monitoring Facility
The Sealy Center for Molecular Medicine (SCMM) Selected Reaction Monitoring Mass Spectrometry (SRM MS) Facility aims to provide UTMB investigators and trainees with
state-of-the-art mass spectrometry-based proteomics and metabolomics
technologies and services.
The SRM facility provides the following technologies and services:
- SRM-based targeted proteomics analysis
Selected reaction monitoring (SRM; plural, MRM, multiple reaction
monitoring) is a ‘targeted’ MS approach for the detection and
quantification of a predetermined set of proteins in a complex
background. In a SRM-MS assay (Figure 1), one or two signature
proteotypic peptides, which are unique to the protein of interest, are
selected to stoichiometrically represent the protein. SRM-MS analysis of
these signature peptides is performed on a triple quadrupole mass
spectrometer (QQQ-MS), an instrument with the capability of selectively
isolating precursor ions corresponding to the m/z of the signature
peptides and to selectively monitor peptide-specific fragment ions (the
combination of m/z of precursor ion and its product ions are called
precursor-product ion transitions). SRM-MS assay can be thought of as
the MS equivalent of the traditional Western blot, in that specific
proteins are targeted and quantified. However, SRM assays do not require
the generation of high-affinity antibodies, and yet have better
specificity of quantification. Specifically, SRM-MS can be used for
studying the dynamics of signaling pathways and biomarker verification.
The SRM facility's proteomics analysis services include:
- Development of new SRM assays for proteins
- Quantification of a set of pre-selected proteins
- Biomarker verification
- Quantitative proteomics and phosphoproteomics profiling
Quantitative proteomics and phosphoproteomics is a technique to
determine the relative abundance changes of proteome and
phosphoproteome. It usually refers to shotgun proteomics approach in
which high-resolution, high mass accuracy mass spectrometer and
label-free or stable isotope methods, such as iTRAQ and H218O, are used.
The phosphorylated peptides are enriched with immobilized metal
affinity chromatography (IMAC) technology. The quantification is
achieved by measuring the intensity of MS signal of the precursors of
peptides or iTRAQ reporter ion (Figure 2). The SRM facility provides this
service using high-resolution, high-mass accuracy Q Exactive Orbitrap
mass spectrometer and label-free or stable isotope methods such as iTRAQ
and H218O. Please inquire about experiment design and cost.
- Posttranslational Modification (PTM) profiling
The SRM facility provides services for identification of other PTMs.
Please contact us for more information and other types of
posttranslational modification analyses that can be performed.
- Protein and PTMs Identification
Protein and PTMs Identification can be performed from SDS-PAGE gel.
- Quantitative metabolomics profiling
The SRM facility provides global metabolomics profiling using
accurate mass measurements with a high-resolution, high mass accuracy Q
Exactive Orbitrap mass spectrometer. The schematic workflow for
metabolomics profiling is shown in Figure 3.
- Targeted metabolites and small molecules analysis
- Development of new SRM assays for metabolites or other small molecules
- Quantification of a set of pre-selected metabolites or
small molecules. The SRM facility has established SRM assays for amino
acids, biological acids and bases, and some lipids
- Pharmacokinetics analysis