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 measured 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 pure 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 observed in aqueous solutions containing l -leucine.