The Amino Acid Compositions of Several Wool Fractions as Determined by Paper Chromatography

A paper chromatographic study of the amino acid compositions of several histo logical fractions of wool has been conducted. The fractions considered were epicuticle, cortical cell membranes, paracortex, and regenerated oxidized keratin. Samples of these fractions were hydrolyzed with hydrochloric acid, and quantitative analyses of the amino acid content of these hydrolysates were accomplished through a modification of the standard two-dimensional paper chromatographic technique. The epicuticle was found to contain normal amounts of cystine but extraordinarily large quantities of aspartic acid and glutamic acid. In addition to confirming the results of the phosphotungstic acid analyses for cystine reported in a previous paper [14], the chromatographic studies of the paracortex showed large amounts of the basic and small amounts of the dicar boxylic amino acids to be present. The extremely low total of amino acid content found in the cortical cell membranes indicated the possible presence of some nonprotein constituent.