Protein Estimation Assays
G-Biosciences offers a unique selection of protein estimation assays that are improvements on the Biuret Protein Assay, Lowry Protein Assay, BCA Protein Assay and Bradford Protein Assays. Protein estimation assays, also known as Protein quantification assays or protein quantitiation assays, for determining protein concentration are one of the most widely used methods in life science research. Protein estimation of protein concentration is necessary in protein purification, electrophoresis, cell biology, molecular biology, and other research applications.
Bradford Protein Assays
- CB™ Protein Assay: An improved Bradford Protein Assay (Coomassie Protein Assay) with a 0.5-50µg linear response. Supplied as a trial size, with BSA Protein Assay Standards or a unique Non-Animal Protein Assay Standard.
- CB-X™ Protein Assay: Based on our improved Bradford Protein Assay, this assay is supplied with a proprietary clean-up option making this assay a detergent compatible and reducing agent compatible Bradford Protein Assay. For simple aqueous samples, the clean up step is not required.
- DCB™ Protein Assay: A detergent compatible Bradford Protein Assay (Coomassie Protein Assay) that contains proprietary reagents suitable for samples containing detergents including SDS and Triton-X 100. No additional clean up steps are required.
- RED 660™ Protein Assay: Based on the Bradford Protein Assay, but uses a proprietary dye to enhance the dye binding assay. The improved dye offers greater linearity, greater color stability, and greater compatibility with detergents, reducing agents and other interfering agents compared to the Coomassie assays.
- SPN™ Protein Assay: A novel protein assay, suitable for single sample protein estimation, that detects as little as 0.5µg protein. Using a protein binding spin column, interfering agents are washed away and then a protein binding dye is added and protein bound dye is eluted and measured.
- SPN™-htp Protein Assay: A novel protein assay, suitable for high throughput protein estimation, that detects as little as 0.5µg protein. Using a protein binding 96 well spin column plate, interfering agents are washed away and then a protein binding dye is added and protein bound dye is eluted and measured.
BCA Protein Assays
- BCA Protein Assay: Also known as the Smith Assay, is a highly sensitive colorimetric assay that is compatible with detergent solubilized protein solutions. Available in two sizes with either BSA Protein Assay Standards or a unique Non-Animal Protein Assay Standard.
- Micro BCA Protein Assay: A highly sensitive colorimetric assay that is compatible with detergent solubilized protein solutions. This modification of the BCA Protein Assay is suitable for dilute protein samples (0.5-20µg/ml).
- Reducing Agent Compatible BCA Protein Assay: Based on our BCA Protein Assay and supplied with the Reducing Agent Compatibility Agent (RACA) that modifies reducing agents to limit their effect on the reduction of the assay’s copper ions, preventing inhibition of the assay. The use of RACA allows for samples containing up to 5mM DTT, 10mM TCEP or 35mM ß-mercaptoethanol.
Fluorescent Protein Assay
- FluoroRed™ 600 Protein Assay: A rapid and highly sensitive fluorescent dye based assay that is comprised of fluorescent amine group binding dye, which has different absorption and emission spectrum in conjugated and non-conjugated form. The dye bind to the proteins through their amine groups and upon binding the absorption and emission spectrum shifts to 500/600nm (Ex/Em). The absorption can be read anywhere between 490±10 nm and emission between 600±10 nm.
Lowry Protein Assays & Biuret Protein Assays
These assays are all based on the reaction of copper ions with the peptide bonds.
- NI™ (Non-Interfering™) Protein Assay: A highly sensitive, colorimetric protein assay that overcomes interference of common laboratory agents present in protein solutions and shows minimal protein-to-protein variation. Uses a proprietary clean-up step to remove all laboratory interfering agents.
- ML Protein Assay: A modified Lowry Protein Assay that is compatible with a wide variety of detergents used in protein research in addition to other common reagents such as EDTA and Tris.
- CL Protein Assay: A reducing agent Compatible Lowry Protein Assay that is compatible with common laboratory agents known to interfere with Lowry protein assays, including reducing agents (dithiothreitol (DTT), ß-mercaptoethanol and TCEP), detergents, chelating agents, amines, sugars, strong chaotropic buffers, salts, drugs, antibiotics, cobalt and other common laboratory agents.
Test Strip Based Protein Assays
- Protein dotMETRIC™ Protein Assay: A novel test strip protein estimation assay that uses as little as 1µl sample and detect as little as 2ng BSA. The assay is resistant to most common laboratory agents and shows no protein-to-protein variations.
Although there are a wide variety of protein assays available, none of the assays can be used without first considering their suitability for the application. Each method has its own advantages and limitations and often it is necessary to obtain more than one type of protein assay for research applications.For additional information on protein assays, read the Protein Assays Handbook & Selection Guide.