Complementary peptide sequence coverage using alternative enzymes for on-line digestion with a triaxial electrospray probe.

Using alternative enzymes for on-line digestion with a triaxial electrospray probe extends sequence coverage. This is the first report of utilization of our triaxial probe for on-line analysis with enzymes other than pepsin, suggesting potential for broader application. The probe allows access to processes occurring on a timescale and/or involving substrate conformations complementary to those for conventional (off-line) digestion. Some of the features observed in application to Abeta fibrils are suggestive of unique reactive intermediates during dissolution. Data obtained with enzyme mixtures suggest synergistic effects.