Table 2.

Summary of proteolytic cleavage of inactivated DDAH with endoprotease V8^a

DDAH sequence positions	Calc’d peptide	Observed peptide
Plus leader (−18 to 0)	Mass (Da)	Mass (Da)b
95-105	1322.70	1322.72
95-114	2275.20	2275.22
95-129	3910.90	3910.92
106-114	970.51	970.53
106-129	2606.21	2606.24
115-129	1653.72	1653.72
115-129 + Oxc	1669.71	1669.72
115-129 + 2 Ox	1685.71	1685.71
130-146	1829.94	1829.96
130-146 + Ox	1845.94	1845.95
137-146	1100.60	1100.61
137 + 146 + Ox	1116.60	1116.60
147-158	1280.72	1280.74
147-171	2746.59	2746.60
159-171	1483.88	1483.88
159-180	2403.32	2403.35
159-186	3090.69	3090.72
172-186	1624.82	1624.83
211-223	1544.82	1544.84
211-223 + Ox	1560.82	1560.82
211-234	2843.61	2843.63
224-234	1316.79	1316.81
224-239	1848.01	1847.98
235-254 + Me-Pyrd	2353.12	2353.14
240-254 + Me-Pyr	1821.90	1821.92
240-254 + Me-Pyr + Ox	1837.90	1837.91
240-254e	1730.86	1730.90

^aComparison of average calculated peptide masses for up to two missed cleavage sites and two oxidations. Amino acid numbering is assigned to match that of Protein Data Bank entry 1H70.

^bMasses are reported with errors of ± 0.05 Da.

^cOx stands for addition of +16 Da for one calculated oxidation.

^dMe-Pyr stands for the 2-methyl-pyridine adduct (10) shown in Scheme 3.

^ePeptide mass is taken from a digest done in parallel using an uninhibited DDAH sample.