heme-L-cysteine (12-ethenyl-7-[(1S)-1-([(2R)-2-amino-2-carboxyethyl]sulfanyl)ethyl]-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-bis[2-carboxyethyl]-N21,N22,N23,N24)-ferrate 4-[1-(S-cysteinyl)ethyl]protoporphyrin IX 616.17730712890625 616.5 719.18646240234375 719.6400146484375 A protein modification that effectively results from forming an adduct between a cysteine residue and the porphyrin compound heme b, (7,12-diethenyl-3,8,13,17-tetramethylporphyrin-2,18-dipropanoato)iron. BINDING Heme (covalent; via 1 link) C C 34 Fe 1 H 32 N 4 O 4 S 0 C 37 Fe 1 H 37 N 5 O 5 S 1 From DeltaMass: Average Mass: 617. Heme HemeCys1 MOD:00144 PSI-MOD S-Heme (on Cysteine) Unimod:390 cysteinyl heme heme heme-L-cysteine natural porphyrin modified residue metal or metal cluster coordinated L-cysteine residue