Determination of the degree of hydrolysis of partial acid hydrolysates of casein and fibrin.

White and Elman (1) in 1942 described condit,ions for the partial acid hydrolysis of proteins under which most of the tryptophane was retained undamaged. These hydrolysates appeared suitable for intravenous injection, as was reported briefly in the same communication. Studies have since been carried out by Risser, Schenck, and Frost (2) in these laboratories which demonstrate that partial acid hydrolysates prepared from casein and fibrin are well utilized by the dog when administered by vein. Of particular interest in regard to the nature of such hydrolysates is the degree of hydrolysis; i.e., the ratio of free amino acids to those in peptide linkage and the relative size of the peptide fragments. Experiments were made to determine the variation in the degree of hydrolysis of casein and fibrin which would occur at intervals ranging from 2 to 24 hours in boiling 2.8 N sulfuric acid. Experiments were also carried out to show the effect of rapid hydrolysis in the autoclave at elevated temperature.