has functional parent N-acetyl-L-cysteine S-diphytanylglycerol diether-L-cysteine N-acetyl-S-archeol-cysteine 676.67333984375 677.17999267578125 779.68255615234375 780.32000732421875 N-term natural C 45 H 88 O 3 A protein modification that effectively converts an L-cysteine residue to N-acetyl-S-archeol-L-cysteine. C 48 H 93 N 1 O 4 S 1 PSI-MOD MOD:00897 C modified L-cysteine residue