ELISA / Western Blot / Alpha Technology
Biomarker Discovery

Protein Detection Methods

At Reaction Biology, protein detection supports biomarker discovery, monitoring of pharmacodynamic markers, and MoA analysis.

We offer three methods for protein analysis:

  1. ELISA (enzyme-linked immunosorbent assay) is a high-throughput method to quantify proteins in cells or other biological samples, including liquids. The protein of interest is detected with specific antibodies and quantified with high accuracy.
  2. Western Blot Services enable the detection of proteins in biological samples based on specific antibodies and the molecular size of the protein. Our Western Blot Service provides qualitative and quantitative means to investigate the modulation of protein expression or post-translational modifications.
  3. Alpha technology comprises AlphaLISA and AlphaScreen, which are homogenous assay formats for the detection of protein-protein interactions or protein modifications such as phosphorylation. The Alpha technology is a highly sensitive method enabling high-throughput screening with no wash steps guaranteeing reproducible results. The assay requires two antibodies that specifically bind to the protein of interest.

In addition, we also offer multiplexing methods for protein science including multiplex ELISA via Meso Scale Discovery technolgy and flow cytometry.

In most cases, our protein detection methods can be custom-tailored to the client’s specific needs. Connect with our scientific team to find out how we can best support your research goals.

Additional Information about Protein Detection Methods

  • Western Blot Principle
  • ELISA Principle
  • Alpha Technology Principle
Western Blot Principle

Our Western Blot Service is a highly sensitive low throughput method for protein identification via antigen-specific antibodies and molecular weight.

In the first step, the proteins are solubilized via a detergent from tissue or cells. Next, the proteins are separated by their molecular size via SDS-PAGE before being transferred onto a membrane. The proteins are detected by specific antibodies labeled with fluorochromes quantified with a near-infrared imager.

The more sensitive enhanced chemiluminescence (ECL)-based imaging can be used as an alternative detection method.

ELISA Principle

ELISA is well established at Reaction Biology for quantification of proteins in a high-throughput format.

The target protein can be quantified from liquid samples such as blood plasma or cell culture medium or solid samples including tissues or cultured cells. After lysis, the lysate is applied to multi-well plates prepared with target-specific capture antibodies immobilized on the plastic surface. The antibody captures the target proteins which in turn are detected by target-specific detection antibodies that are labeled with a fluorochrome for quantification.

Alpha Technology Principle

AlphaLISA and AlphaScreen are homogenous assay formats briefly described as bead-based ELISAs. This high-throughput assay format works without any wash steps making this a fast and reproducible method.

Alpha technology relies on two antibodies that bind to the protein of interest at different epitopes. In the example shown above, one antibody binds to LRRK2 kinase; the second antibody binds to the phospho-site of the kinase to detect autophosphorylation. Acceptor and donor beads, each covered with one antibody, are brought together when the antibodies bind the same protein. Laser excitation of the donor beads releases thousands of singlet oxygens which can travel up to 200 nm in solution allowing the investigation of larger protein complexes (in comparison, the reach of TR-FRET is only 10 nm). The singlet oxygen initiates a cascade of reactions inside the acceptor beads resulting in luminescence/fluorescence.