Vs. protein concentration

Determination of the extinction coefficient is a relatively straightforward task. The target protein is diluted to give live different concentrations. These samples are then divided into two aliquots. Amino acid analysis (AAA) accurately determines the protein concentration of one set of samples at the live concentrations, and the absorbance at 280 nm (A280) is measured for the other set of samples. The slope of a plot of A2s0 vs. protein concentration by AAA yields the extinction coefficient. 

Fig. 2. FPA vs protein concentration in cultivation broth after cultivation of fungi on cellulose ( + ) and xylan ( O ). Each point in the plot represents the final protein concentration and the corresponding measured FPA in the cultivation broth for each fungus on each substrate.

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