L-3',4',5'-trihydroxyphenylalanine 195.05316162109375 195.1699981689453125 31.989828109741210938 32.0 Dioxidation O 2 natural L-3',4',5'-trihydroxyphenylalanine dihydroxy MOD:00268 L-3,4,5-TOPA C 9 H 9 N 1 O 4 35Hy2Tyr MOD_RES 3',4',5'-trihydroxyphenylalanine none PSI-MOD From DeltaMass: Average Mass: 32 3,4,6-Trihydroxy-Phenylalanine (from Tyrosine) (TOPA) (S)-2-amino-3-(3,4,5-trihydroxyphenyl)propanoic acid A protein modification that effectively converts an L-tyrosine residue to L-3',4',5'-trihydroxyphenylalanine. Y dihydroxylated residue hydroxylated tyrosine