monohydroxylated tryptophan 5-hydroxy-L-tryptophan 15.994915008544921875 16.0 202.0742340087890625 202.2100067138671875 none (S)-2-Amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid A protein modification that effectively converts an L-tryptophan residue to a 5-hydroxy-L-tryptophan. W MOD:02107 O 1 C 11 H 10 N 2 O 2 PSI-MOD hypothetical