3.4 N-Terminal amino Acid Sequencing

5. N-terminal Amino Acid Sequencing

• Purpose: Identify the sequence of amino acids at the protein’s N-terminus.
• Techniques:
  • Edman Degradation: Sequential removal of N-terminal residues.
  • Sensitivity: Detects down to fmole (femtomole) levels.
• Challenges:
  • N-terminal blockage by pyroglutamic acid.
  • Complexity when multiple peptides are present.

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6. Quantitation and Interpretation

• Yield Calculation: Accurate quantitation ensures reliable sequencing.
• Example: 1 μg of 10 kDa protein yields about 100 pmoles.
• Importance: Correct calculations validate sequencing results.