TABLE V. Matching tryptic peptides for PO-1 and PO-2 co-purified with SPC4s.

The serpin-4-protease complex (SPC4) bands were cut out and subjected to in-gel trypsin digestion. The peptides extracted were analyzed by MALDI-TOF mass spectrometry. The experimental peptide masses matching peptides of PO-1 and PO-2 were obtained from co-migrating SPC4-5 and SPC4-4 bands, respectively. The numbering of peptide residues of PO-1 (GenBank^TM accession number AAC05796) and PO-2 (accession number AAC37243) refers to the pro-forms. The peptides with putative residue modifications are indicated by superscript greek as follows: α, one cysteine carbamidomethylation by iodoacetamide; β, one methionine oxidation.

Measured mass (MH+) from SPC4-5 band	Matched PO-1 peptide		Measured mass (MH+) from SPC4-4 band	Matched PO-2 peptide
	Residues	Computed mass (MH+)		Residues	Computed mass (MH+)
2923.355	96–119α, β, β	2923.346	2367.231	123–141α	2367.174
1871.793	105–119α, α	1871.827	1311.691	160–170	1311.670
2174.046	177–195	2174.055	708.408	202–206	708.383
2857.330	201–223	2857.360	1909.011	237–251	1908.991
1910.959	231–245	1910.970	1752.887	238–251	1752.890
2843.411	334–359	2843.417	1897.928	267–281	1897.913
2673.154	360–382	2673.169	1155.501	290–299	1155.585
1749.795	383–398	1749.805	1729.843	305–319	1729.854
1417.741	450–461	1417.744	1802.871	385–400	1802.864
3220.482	475–502	3220.549	844.420	401–406	844.399
			1591.820	407–419	1591.791
			1324.719	482–491	1324.703
			1199.637	519–528	1199.617
			1503.846	537–550	1503.817
			1870.934	551–566	1870.919
			1087.615	567–576	1087.538
			2621.256	577–598α, α	2621.222
			2408.124	578–598α	2408.099
			1630.748	627–640	1630.728
			1127.566	682–691	1127.570