Application of trinitrophenylation for the measurement of alpha-amino residues resulting from peptic digestion.
A sensitive and precise method for the measurement of peptic activity on protein substrate is described. alpha-Amino residues formed by pepsin digestion are photometrically measured by comparing the absorbances of digested and nondigested material which has been trinitrophenylated. The usual problem of high reagent-blank absorbance is eliminated by using an anion exchange resin, Dowex 1-X8. In contrast to Anson's method, the procedure requires only 1/100 the quantity of protein substrate for analysis. It was proved to be particularly useful for the estimation of initial rates of proteolysis.
Application of trinitrophenylation for the measurement of alpha-amino residues resulting from peptic digestion. A sensitive and precise method for the measurement of peptic activity on protein substrate is described. alpha-Amino residues formed by pepsin digestion are photometrically measured by comparing the absorbances of digested and nondigested material which has been trinitrophenylated. The usual problem of high reagent-blank absorbance is eliminated by using an anion exchange resin, Dowex 1-X8. In contrast to Anson's method, the procedure requires only 1/100 the quantity of protein substrate for analysis. It was proved to be particularly useful for the estimation of initial rates of proteolysis.