Protein analytics (Tycho)

The "Tycho" measures the intrisic fluorescence of proteins (and DNA when modified with the fluorescent 2-aminopurin) that changes upon slowly heating from 30-95°C. Protein fluorescence (wavelength, quantum yield) strongly depends on the number of tryptophane(s) and tyrosine(s) and their location within the folded protein or, after denaturation, in contact with water molecules. Upon denaturation, that brings W and Y from a hydrophobic to a hydrophilic environment, a spectral shift occurs accompanied by a change of fluorescence intensity that is measured. This way, the state of a protein in solution can be analysed. For example, protein stability in a specific buffer, the effect of freeze-thaw cycles, or the back folding to the natural state can be assessed. Moreover, aliquots can be compared with respect of identity and integrity of protein samples. Measurements are conducted in quartz capillaries at protein concentrations of ca. 0.1-1 mg/mL and consume 8-9 µL. Six capillaries can be measured in parallel within 3 min.