Assignment of all four disulfide bridges in echistatin.

摘要: Echistatin is a 49-amino-acid protein fromEchis carinatus venom. It contains four disulfide bonds. Since the bonding critical for biological activity, it very important to assign linkage in this protein. was incubated 250 mM oxalic acid at 100°C 4 hr under nitrogen. Under these conditions, many overlapping disulfide-containing peptides were identified by ionspray mass spectrometry. Ionspray MS/MS data indicate that bonds are Cys 2–Cys 11, 7–Cys 32, 8–Cys 37, and 20–Cys 39. To our knowledge, first time all echistatin have been assigned one experiment without bond exchange. This approach, which combines hydrolysis MS/MS, may be useful assigning bridges other proteins from disintegrin family.