The term protein analysis encompasses a broad range of techniques used in research, biomanufacturing, and clinical applications. It can refer to the analysis of a specific protein or of interactions between proteins or to the detection and quantitation of proteins in a sample or product. Methods used for protein analysis (alone or in combination) include SDS-PAGE, western blotting, surface plasmon resonance, ELISA, and other immunoassays. In clinical applications, certain types of lateral flow and flow-through immunoassays help detect antigens.
Electrophoresis refers to the use of an electric current to propel molecules through a matrix such as an agarose or acrylamide gel. Because it separates molecules on the basis of size, charge, or shape, electrophoresis is useful in analysis of those same features of proteins. Several types of electrophoresis are used in protein analysis:
Polyacrylamide gel electrophoresis (PAGE)
In PAGE, a porous acrylamide gel matrix is used to separate proteins based on size or charge. Proteins are propelled through the gel by an electric current.
This is PAGE with the detergent SDS added to the acrylamide gel. SDS binds to and denatures proteins, breaking them down into smaller, negatively charged subunits. Because the subunits have similar charges once bound to SDS, SDS-PAGE is suited for separating proteins by size.
Isoelectric focusing (IEF)
In IEF, proteins are separated based on native isoelectric point (pI).
2-D electrophoresis combines SDS-PAGE and IEF to separate proteins by size and isoelectric point.
Once separated on a gel, proteins can be visualized in the gel by staining or transferred to a membrane for immunostaining (western blot) and analysis.
Western blotting, also called immunoblotting, involves electro-transfer of proteins onto a membrane (often made of PVDF) that can then be incubated with reagents or antibodies to detect the presence of or quantify proteins.
ELISA (enzyme-linked immunosorbent assay) is a plate-based assay technique for detecting and quantitating peptides, proteins, antibodies, or hormones. ELISA uses antibody-antigen binding and a reporter enzyme system to detect target molecules in microplates. HCP ELISA detects the presence of host cell proteins as part of quality control.
Surface plasmon resonance (SPR) is a label-free detection method for real-time analysis of biomolecular interactions.
Protein analysis equipment
We offer a wide variety of protein analysis equipment for processes like surface plasmon resonance (SPR), electrophoresis, and western blotting. They include:
- Supplies such as nitrocellulose and PVDF membranes, reagents, and equipment for western blotting and fluorescent protein detection.
- Electrophoresis unit and reagents for 2D protein analysis, PAGE, and IEF.
- Equipment for detecting and quantifying host cell proteins (HCP) while validating HCP ELISA results.
- Reagents, membranes, and accessories for lateral-flow or flow-through ELISAs and assays.
- High-resolution molecular imagers with laser scanning or CCD cameras for quantitating proteins.
- Buffers and kits for protein lysis, extraction, and clean-up for sample preparation.
- SPR analysis products for screening and characterizing molecular interactions.
Protein analysis equipment and supplies FAQs
Below are a few frequently asked questions about protein analysis equipment and supplies:
Which tests are used for protein analysis?
There are many protein analysis techniques. Common techniques include:
- SDS-PAGE combined with gel staining or western blotting
- Isoelectric focusing
- 2D gel electrophoresis
- HCP ELISA
What is the purpose of protein analysis?
Protein analysis helps researchers and biomanufacturers understand the function and impact of proteins and screen samples for the presence and quantity of proteins.