Protein Concentration Determination Methods

Concentrations of purified proteins were determined by the densitometry of bands on Coomassie Blue R-250 stained SDS-PAGE gels using carbonic anhydrase as a standard and a ChemiDoc MP imaging system (Bio-Rad Laboratories). Fluorescent proteins were detected by direct in‐gel fluorescence imaging using the same ChemiDoc imaging system. Alexa647 and mNeon concentrations were determined using ε₆₅₀ = 270,000 cm⁻¹ M⁻¹ and ε₅₀₆ = 116,000 cm⁻¹ M^{−142 (link)}, respectively. Western blot bands were visualized by chemiluminescence using the Clarity Max Western blotting kit (Bio-Rad Laboratories, #1705062) and the ChemiDoc imaging system. IMV concentrations were determined as the A₂₈₀ in 2% SDS^{7 (link)}.