Mass Spectrometric Sequence Studies of a Superoxide Dismutase from Bacillus stearothermophilus

Abstract
A partial sequence of the manganese-containing superoxide dismutase from B. stearothermophilus has been determined by mass spectrometry. A new fragmentation reaction at N-terminal proline is described and an in-chain fragmentation, also occurring at proline, has been observed. There is some evidence that the latter cleavage may also occur at other residues. Some differences from the classically determined sequence are reported and the validity of these observations is discussed.