Fractionation of Amino Acids From Hydrolysates in Nonaqueous Systems

Publisher Website
Google Scholar
Abstract
Fractionation of hydrolysates is done as follows: (1) Increments of acid in acetone are brought successively into contact with dry hydrolysate in finely ground state. The reagent with dissolved amino acids is removed. Another increment of reagent is applied to the undissolved hydrolysate, and this is then removed. The hydrolysate is thus separated into many fractions. (2) The hydrolysate is dissolved in a minimal amt. of acid-acetone reagent, and amino acid fractions are dropped out by stepwise introduction of dry NH3. (3) The hydrolysate in soln. is fractionated by stepwise introduction of HC1. (4) Fractionation is done by successive addition to the acetone-reagent-amino acid system of some solvent which is miscible only with acetone. (5) Trichloroacetic acid solns. of amino acids in acetone undergo spontaneous precipitation. As the acid is decomposed, the amino acids progressively precipitate. Fractions obtained by these methods were examined by paper chromatogra phy; from hydrolysates containing 18 or more amino acids the components of a series of 20-60 successive fractions from method 1 differ qualitatively. Those most soluble in the reagent were more abundant in the earlier fractions. When fractions are rechromatographed at successive dilutions, one after another of the amino acids fail to appear on the chroma-togram; this allows appraisal of the quantitative composition of any fraction as to its amino acids. Color reactions show that the amino acids occur only over limited ranges of the successive fractions.

This publication has 1 reference indexed in Scilit: