N-formyl-L-tryptophan N1'-formyl-L-tryptophan 214.0742340087890625 214.220001220703125 27.994915008544921875 28.010000228881835938 hypothetical C 12 H 10 N 2 O 2 A protein modification that effectively converts an L-tryptophan residue to N1'-formyl-L-tryptophan. PSI-MOD This modifications has not been reported as commonly encountered [JSG]. C 1 O 1 N1'FoTrp MOD:01994 none W