Protein Quantification

Absolute Quantification (AQUA)

Absolute Quantification (AQUA) is a targeted quantitative proteomics technique for the absolute quantification of proteins and post-translational modifications in complex protein mixtures using stable isotope–labeled peptides as internal standards. Enzymes with well defined cleavage sites, such as trypsin, are used to generate peptides that can be separated by reversed-phase high-performance liquid chromatography. The abundance of these internal standards and their unlabeled endogenous counterparts can be measured by mass spectrometry with selected reaction monitoring (SRM) or selected ion monitoring (SIM) methods.

This approach allows highly accurate and selective measurements of analyte abundance across many samples and conditions with moderate to high throughput. The method is highly sensitive matching other analytical methods such as radioimmunoassays (RIA) and ELISA.

Current targeted proteins include:

• Lactoferrin (LTF)

• Lactoperoxidase (LPO)

• Immunoglobulins (IgG1, IgG2, IgA, IgM)

• Butyrophilin (BTN)

• Adipophylin (ADPN)

• Mucin 1 (MUC1)

• Lactadherin (PAS67)

• Xanthine Dehydrogenase (XDH)

If you have a target of interest that requires quantitation from a complex matrix of proteins, then contact us to discuss your requirements.

BCA Assay

The BCA assay is a colorimetric assay that quantifies protein content against a known standard by measurement of Cu+ ion binding to bicinchoninic acid (BCA reagent). Cu+ ion content in a sample is driven by the reduction of Cu2+ by protein in an alkaline medium.

Bradford Assay

The Bradford assay is a colorimetric assay that utilises the dye-binding capacity of Coomasie to aromatic amino acids to quantify protein samples against a known standard.

Immunosorbent Assay (ELISA)

MS3 Solutions has extensive expertise in development and performance of enzyme linked immunosorbent assays (ELISA). ELISAs quantify protein based on antibody binding and colorimetric detection. Depending on your research and analytical requirements, there are several ELISA formats that can be discussed.

We provide fast and accurate results at affordable prices. For straightforward quantification, please download the sample submission form.