N-Terminus
N-Terminus — The end of a peptide or protein chain terminated by a free amino group (-NHâ‚‚). Peptide synthesis by Fmoc chemistry proceeds from C- to N-terminus.
What Is the N-Terminus?
The N-terminus (amino terminus) is the end of a peptide chain with a free amino group (-NH2 or -NH3⁺ at physiological pH). Peptide sequences are read left-to-right from N-terminus to C-terminus. The N-terminus is the first residue synthesized in ribosomal translation and the last residue added in SPPS (C-to-N synthesis).
N-Terminal Modifications
- Acetylation: Blocks aminopeptidase degradation and eliminates positive charge
- Pyroglutamate: Cyclized N-terminal Glu or Gln. Natural modification in many peptide hormones
- Fluorophore: N-terminal labeling during on-resin synthesis
- PEGylation: Site-specific N-terminal PEG attachment at slightly acidic pH
Frequently Asked Questions
What is N-Terminus?
The end of a peptide or protein chain terminated by a free amino group (-NHâ‚‚). Peptide synthesis by Fmoc chemistry proceeds from C- to N-terminus.
Why is N-Terminus important in peptide research?
N-Terminus is a fundamental concept in biochemistry as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.