Edman Degradation and Protein Sequencing: Pfu N-acetyl Deblocking Aminopeptidase (Ac-DAP)
Pfu N-acetyl Deblocking Aminopeptidase (Ac-DAP) is a unique exo-type aminopeptidase that liberates blocking groups (formyl, acetyl, and myristyl) from proteins and peptides, releasing amino acids until it reaches the first X-Pro bond. This enzyme has a wide range of substrate specificities and is used to determine short stretches of amino acid sequence in blocked proteins and peptides via mass spectrometry. An additional advantage of using Pfu Ac-DAP is that, since its amino terminus is acetylated, the enzyme itself is not subject to Edman Degradation. Therefore, even if a high ennzyme to substrate (E/S) ratio is used (e.g., E/S = 0.5-1), protein sequencing can follow Edman degradation without the need for an extra purification step.
Note:Pfu Ac-DAP cannot act on non-denatured proteins; therefore, the protein sample must be completely denatured by carboxymethylation for Pfu Ac-DAP digestion.