Source comparison
Structural Comparison: Where the Similarity Ends
Both peptides share the same C-terminal extension, but their N-terminal sequences are entirely different. Full sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro Met-Glu-His-Phe-Pro-Gly-Pro Sequence length 7 amino acids Parent compound Tuftsin (Thr-Lys-Pro-Arg) ACTH(4-7) (M
This comparison does not assign a generated winner or score.
- Both peptides share the same C-terminal extension, but their N-terminal sequences are entirely different.
- Full sequence
- Thr-Lys-Pro-Arg-Pro-Gly-Pro
- Met-Glu-His-Phe-Pro-Gly-Pro
- Sequence length
- 7 amino acids
- Parent compound
- Tuftsin (Thr-Lys-Pro-Arg)
- ACTH(4-7) (Met-Glu-His-Phe)
- Shared motif
- Pro-Gly-Pro (C-terminus)
- Molecular weight
- ~751.87 g/mol
- ~767.9 g/mol
- Proline residues
- 3
- 2
- Net charge at pH 7
- Positive (Lys, Arg)
- Slightly positive (His, partial)
- The C-terminal Pro-Gly-Pro extension was incorporated into both peptides for the same reason: metabolic stability. By capping the C-terminus with proline-glycine-proline, both Selank and Semax resist rapid degradation by many common exopeptidases. This is a shared design principle, not a coincidence.
- What differs fundamentally is the N-terminal pharmacophore — the part of the molecule that drives the primary receptor interactions.