Microquantification of Proteins by Spectrophotometry. Part I: From 190 nm to 1100 nm, Selection of Wavelengths

Abstract Several methods for protein determination have been described. In almost all cases, a detection reagent is involved (Coomassie Blue reagent, bicinchoninic acid, Folin reagent). Proteins quantification determination by measurements in the U.V. region1 have been abandonned because of the weak sensitivity of the apparatus (concentrations of the order of 100 μg/ml) and because of the lack of precision at low wavelengths (far U.V.). Owing to the progress in the performance of equipments, (i) we have been able to show that the reliability of current equipments allowed measurements in the more sensitivity range of proteins (190 to 220 nm) and beyond (220 to 1100 nm) and (ii) we have hence calculated the correlation factors between absorbance values and wavelengths for 17 proteins. It was found that 190 nm and 277 nm were the best wavelengths in far U.V. region for the protein quantification (correlation factor respectively of 0.69 and 0.62). The concentrations of 16 proteins were predicted at 190 nm and...