Protein Mass Spectrometry

Mass spectrometry basics

The expanding field of proteomics involves many unique requirements, particularly in terms of specific reagent needs for mass spectrometry (MS). In order to fulfill these mass spectrometry needs we offer a comprehensive range of reagents to cover your complete workflow, including:

  • For routine MALDI MS calibration, we offer the ProteoMass MALDI Calibration Kits, as well as individual highly purified ProteoMass MALDI matrices and a wide range of well-recognized, prequalified MALDI MS calibrants.
  • Our SILutions products are high quality calibration and internal standards for mass spectrometry, such as stable isotope labeled (SIL) antibodies (SILuMAb) and proteins (SILuProt).
  • Our line of trypsin products is second to none. Trypsin, Proteomics Grade, offers superior sequence coverage while eliminating ambiguous autolytic MALDI peaks. The Trypsin Profile IGD kit enables fast, efficient, completed digestion from PAGE to MALDI.
  • Through our collaboration with SCIEX, we offer a broad range of tagging chemistries for quantitative proteomics, including ICAT®, iTRAQ®, and mTRAQ®, as well as the CYP450 kits.

SOLu-Trypsin Advanced Proteomics Grade Enzymes and Solutions for Mass Spectrometry

The SOLu-Trypsin ready-to-use recombinant trypsin solution (EMS0004) is our exclusive, Advanced Proteomics Grade enzyme that is solution stable for mass spectrometry. Designed to be stable in solution when refrigerated, SOLu-Trypsin can be used immediately without preparation. Other forms of trypsin require thawing or reconstitution and must be discarded if not used immediately. SOLu-Trypsin allows excess product to be saved for future use, thus eliminating unnecessary waste and cost. SOLu-Trypsin is formulated with a high-purity recombinant trypsin, free of chymotryptic activity, to ensure high fidelity digestion with many additional features and benefits, including:

  • Ready to use - no preparation, such as reconstitution or thawing, is required
  • Fits seamlessly into established workflow - no need to modify protocols
  • Eliminates waste - remains stable in the refrigerator after use so there is no need to discard excess product
  • Recombinant, porcine sequence - no chymotryptic activity
  • Stable for short-term use at room temperature in an autosampler or on a liquid handling robot
  • SOLu-Trypsin Rapid Digestion Kit (MSKT0002) allows for trypsin digestion in one hour at 60 °C

SILuProt Protein Standards for Quantitative Mass Spectrometry

SILuProt products are a novel collection of stable isotope-labeled (SIL, or “heavy labeled”) full length proteins designed to be used as mass spectrometry internal standards for quantitative proteomics. The ideal method of optimizing reproducibility and accuracy in protein quantification by mass spectrometry is to add a full-length SIL recombinant protein, equivalent to the native target protein, to the sample at the initial stage of sample preparation. Introduction of an internal standard at the beginning of the MS workflow minimizes variations in quantification due to protein extraction, fractionation, enrichment, proteolysis and analysis. Sigma-Aldrich also offers all of the SILu™Prot products in their unlabeled form, SILu™Lite proteins.

SILuPrEST protein fragments, SILuPep and AQUA Peptide Fragment Mass Spectrometry Standards

SILuPrEST standards generate multiple labeled peptides upon digestion, serving as internal standards for absolute quantification of the corresponding endogenous proteins. The SILuPrEST standards are produced on demand using metabolic labeling with heavy isotope labeled (15N, 13C) Lysine and Arginine residues, with greater than 99% isotopic label incorporation. SILuPrEST concentration is determined with high accuracy and precision by MS-analysis using an N-terminal sequence consisting of a hexahistidine (His6) sequence followed by an Albumin Binding Protein (ABP) present in all SILuPrESTs. Added early in the proteomics workflow, SILuPrEST standards reduce bias due to sample preparation and provide highly accurate quantitation information.

SILuPep products are a collection of stable isotope-labeled (SIL, or “heavy labeled”) peptides designed to be used as mass spectrometry internal standards for quantitative proteomics. In addition, our AQUA peptides allow you to eliminate costly, time-consuming stable isotope labeling steps to focus your analysis on significant protein biomarkers.

Mass Spectrometry Calibration Standards

We offer a variety of mass spectrometry calibration standards for quantitative proteomics. These high-quality products help to standardize your proteomics research and provide the best quality control for the precision and accuracy of your MS data. Our products include Universal Proteomics Standard (UPS) with well-defined, well characterized standards made up of 48 proteins 6-83 KD (UPS1) or 6 mixtures of 8 proteins (UPS2). Additionally, the MS Qual/Quant QC Mix (MSQC1) contains 6 trypsin digested human proteins and 14 SIL peptides, while the MS Retention Time Calibration Mix (MSRT1 and MSRT2) are injection-ready mixtures containing 14 stable isotope-labeled peptides or 9 native proteins, respectively.

Stable Isotope Labeled Compounds

Stable isotope labeled compounds enable the specific qualitative and quantitative study of metabolites. A stable isotope-resolved metabolomics (SIRM) approach aids in the identification and quantification of specific metabolites found in complex matrices. Both tracer and flux studies benefit from the use of stable isotope labeled metabolites coupled with NMR and/or mass spectrometry analysis.

Quantitative proteomics using Mass Spectrometry is emerging as a complimentary technology to elucidate the structure and function of proteins. We offer stable isotope labeled products for metabolic labeling, enzymatic labeling, chemical labeling and stable isotope labeling with amino acids in cell culture. We also offer the widest variety of protected amino acids for peptide synthesis.

Sciex iChemistry Solutions

In collaboration with SCIEX, we now provide their global distribution mass spectrometry-based tagging chemistries, SCIEX iChemistry Solutions, for use in basic research and applied markets. The two companies together provide total reagent solutions for quantitative proteomics, to allow researchers to dig deeper into complex biological systems, analyze prospective biomarkers, and deliver results. You now have access to the largest selection of high-quality tools for workflows to enable biomarker analysis. Specifically, in protein biology, our offerings include the SCIEX ICAT®, iTRAQ®, mTRAQ®, and CYP450 product lines for quantitative proteomics.

With our targeted selection of kits, tagging reagents, calibrants, and MS standards, we are committed to meet your mass spectrometry reagent needs.