Table 1. MALDI–TOF MS data obtained after tryptic digestion of ferric and ferrous S160C.

Numbering is as used previously [10]. Fragments containing Cys¹⁶⁰ are in bold. Fragments with a molecular mass <600 Da were not detected under the conditions used and are not indicated. nd, not detected.

Residues	Peptide sequence	Calculated mass	Observed mass (ferric)	Observed mass (ferrous)
−9–3 (His6 tag)	GSHHHHHHGSGK	1314.60	1314.86	1314.86
4–14	SYPTVSPDYQK	1284.61	nd	1284.86
32–38	CAPLILR	785.47	785.61	785.61
39–50	LAWHSAGTFDSK	1319.64	1319.90	1319.89
53–61	TGGPFGTIK	877.48	nd	877.64
62–79	HQAELAHGANNGLDIAVR	1885.96	1886.36	1886.35
80–85	LLEPIK	712.46	nd	nd
86–119	EQFPIVSYADFYQLAGVVAVEITGGPEVPFHPGR	3689.86	3690.59	3690.61
120–130	EDKPEPPPEGR	1250.60	1250.88	1250.85
137–142	GSDHLR	684.34	684.46	684.46
148–170	AMGLSDQDIVALCGGHTIGAAHK	2265.11	2265.56	nd
148–170+haem	AMGLSDQDIVALCGGHTIGAAHK	2881.61	nd	2879.99
173–199	SGFEGPWTSNPLIFDNSYFTELLTGEK	3049.45	3050.17	3050.15
200–209	DGLLQLPSDK	1085.58	1085.88	1085.86
210–223	ALLTDSVFRPLVEK	1587.91	1588.25	1588.22
224–241	YAADEDVFFADYAEAHLK	2074.94	2075.35	2075.39
242–250	LSELGFAEA	936.47	nd	nd