Protein Detection

We offer a broad range of tools for detecting and quantifying proteins, from traditional immunological detection reagents to novel methods that monitor protein abundance in live cells.

Protein labeling products include HaloTag® Interchangeable Labeling Technology—a versatile protein analysis tool used to image live or fixed mammalian cells, purify proteins, investigate protein interactions and more. The HiBiT protein tagging system provides a powerful method for monitoring and quantifying proteins at endogenous expression levels with a simple luminescent signal.

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Protein Quantitation and Detection Basics

The detection and quantitation of individual proteins is one of the fundamental aspects of proteomics. Immunological-based methods such as quantitative enzyme-linked immunosorbent assays (ELISA), Western blotting and dot blotting are very common and sensitive assays for protein detection, and they use antibodies that react specifically with entire proteins or specific epitopes (e.g., fusion tags) after cell lysis. Detection techniques are typically based on chemiluminescence or fluorescence.

For live-cell detection of proteins, fluorescence imaging microscopy is now routinely used. The most common and conventional method is the use of intrinsically fluorescent proteins (FPs) related in structure or sequence to green fluorescent protein (GFP). Alternatively, a series of self-labeling enzymes have been developed that can covalently attach a fluorescent ligand to one of its own amino acid residues. These enzymes are similar in size to FPs. If these enzyme domains are fused in frame to a protein, the pair can be labeled by introducing a cell-permeable fluorescent ligand, which covalently reacts with the fusion tag.