Solubilities of L-cystine, L-tyrosine, L-leucine, and glycine in their water solutions

The solubilities of four amino acids, L-cystine, L-tyrosine, L-leucine, and glycine, in aqueous solutions containing another amino acid have been meas ured at 298.15 K, 308.15 K, and 318.15 K. In aqueous solutions containing L -cystine and L-tyrosine, which have a low solubility, the solubility of the other amino acids is similar to that in pure water except for L-cystine in water + L-tyrosine. On the other hand, compared to their solubilities in p ure water, in aqueous solutions containing glycine, which is quite soluble, a large variation in the solubilities of all the amino acids can be seen. Considerable variations in the solubility of L-cystine or L-tyrosine are ob served in aqueous solutions containing L-leucine.