L-cysteinyl molybdopterin molybdopterin 520.280029296875 521.88409423828125 623.42999267578125 624.89324951171875 true PSI-MOD C 10 H 11 N 5 O 8 P 1 S 2 Mo 1 natural C OBSOLETE because redundant with MOD:00151. Remap to MOD:00151. C 13 H 16 N 6 O 9 P 1 S 3 Mo 1 MOD:00815 none