Protein concentration can be determined by the absorbance at 205 nm or 214 nm. It is especially useful when absorbance at 280 nm cannot be used in the lack of sufficient number of triptophanes and tyrosines. Another advantage of measuring at these two wavelengths is that, because of the high extinction coefficients, the CD samples can be directly measured. If the spectropolarimeter is capable of accurately converting the HT values to absorbances, then the concentrations can be determined right from the CD measurements after subtracting the baseline absorptions. Extinction coefficients at 205 and 214 nm can be calculated from the amino acid sequence.