Detailed Explanation
The end of a peptide chain bearing a free amino group (–NH₂). By convention, peptide sequences are always written and read from N-terminus (left) to C-terminus (right), reflecting the direction of biological synthesis — the ribosome adds amino acids starting at the N-terminus and extending toward the C-terminus.
The N-terminal amino acid is the first residue synthesized and determines the peptide's half-life in the cell (the N-end rule of protein degradation). N-terminal acetylation occurs on ~80–90% of human proteins, protecting them from aminopeptidase degradation. In SPPS, peptides are built in the opposite direction: C-to-N.
Key Facts
- The end of a peptide chain bearing a free amino group (–NH₂).
- By convention, peptide sequences are always written and read from N-terminus (left) to C-terminus (right), reflecting the direction of biological synthesis — the ribosome adds amino acids starting at the N-terminus and extending toward the C-terminus.
- The N-terminal amino acid is the first residue synthesized and determines the peptide's half-life in the cell (the N-end rule of protein degradation).
- N-terminal acetylation occurs on ~80–90% of human proteins, protecting them from aminopeptidase degradation.
- In SPPS, peptides are built in the opposite direction: C-to-N.
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