“…Precipitation of amino acid hydrates has been reported in literature. [27][28][29][30][31][32] For a couple of amino acids, such transformations in solutions are reported, for example Ser, 33 Lys, 34 Asn 19 , Pro 19 which form hydrates in aqueous solutions. Another example is cysteine, which is shown to dimerize to cystine in solution and in contact with oxygen.…”