sulfated residue 79.956817626953125 79.956817626953125 80.06999969482421875 80.06999969482421875 O 3 S 1 X PSI-MOD O 3 S 1 Sulfo O-Sulfonation A protein modification that effectively substitutes a sulfonyl group for the hydrogen atom of a hydroxyl or sulfanyl group. natural none Sulphonation (SO3H) (of PMC group) SulfRes MOD:00695 From DeltaMass: Average Mass: 80. sulfur containing modified residue