Recombinant E.coli FITC protein

Fluorescein isothiocyanate (FITC)-conjugated recombinant proteins are engineered biomolecules widely used as fluorescent probes in biomedical research and diagnostics. Recombinant proteins are produced through genetic engineering, where target proteins are expressed in host systems (e.g., E. coli, mammalian cells) with precise control over sequence and post-translational modifications. FITC, a derivative of fluorescein, is a small organic fluorophore that emits green fluorescence (~520 nm) when excited by blue light (~495 nm). Its isothiocyanate group enables covalent conjugation to primary amines (-NH₂) in proteins, typically under mild alkaline conditions, forming stable thiourea bonds.

The combination of recombinant protein technology with FITC labeling merges molecular specificity with optical detectability. Recombinant proteins retain their native structure and function after labeling, allowing applications in tracking protein localization, receptor-ligand interactions, and intracellular trafficking. FITC’s high quantum yield and photostability make it suitable for techniques like flow cytometry, fluorescence microscopy, and ELISA. However, FITC has limitations, including pH sensitivity (fluorescence quenches below pH 8) and susceptibility to photobleaching.

These labeled proteins are particularly valuable in immunology (e.g., antibody detection), cell biology (live-cell imaging), and drug development (high-throughput screening). Commercial FITC-conjugated recombinant proteins often undergo rigorous quality control to ensure consistent labeling ratios and minimal batch variability. Alternatives like site-specific labeling (e.g., using unnatural amino acids) are emerging, but FITC remains popular due to its cost-effectiveness and established protocols. Proper storage (light-protected, -20°C) is critical to maintain fluorescence intensity and protein stability over time.