2. FITC from SIGMA)
Fluorescein-labeled protein are immunochemical reagents currently widely used in immunopathology, cytochemistry, flow cytology and pathology. Under alkaline buffer conditions, FITC binds to the free amino groups of the protein to form a fluorescein-labeled protein.
The protein was dialyzed with PBS (1kD dialysis bag), added NaHCO3 to adjust the pH to 9.5, then connected to FITC, protected from light for 2h, centrifugation to remove denatured protein, dialysis to remove free FITC and desalting The protamine-FITC complex is obtained. After centrifugation, concentration, and protein quantification, protein was collected.
NOTE：Centrifuge before use to avoid waste caused by reagents sticking to the tube wall or bottle cap.