Rapid analysis of enzymatic digests of a bacterial protease of the subtilisin type and a "bio-engineered" variant by high-performance liquid chromatography-frit fast atom bombardment mass spectrometry.

Amino acid sequencing of a subtilisin-type bacterial protease and a bio-engineered variant was carried out by investigating various enzymatic digests using HPLC-frit fast atom bombardment MS methods. The fast atom bombardment mass spectral data allowed rapid identification of the enzymatically generated peptides and differentiation between both proteins. The feasibility of determining the positions and nature of mutations in the amino acid sequence depends mainly on the size of the peptides containing the modifications.