The redox-active amino acids of Hb. Hb surface-exposed residues (in tetramer or dimer form) are in bold font. Histidine residues in random coil regions are marked with (*).

Redox-active amino acids	α-Chain	β-Chain
Cys (C)	—	C92
Tyr (Y)	Y24, Y42, Y140	Y34, Y144
Trp (W)	W14	W14, W36
His (H)	H20*, H45*, H50*, H58, H72*, H87, H89*, H103, H112*, H122	H62, H76*, H91, H96*, H145, H142