Circular Peptide
Circular Peptide — A peptide in which the N-terminus and C-terminus are joined by a peptide bond, creating a closed ring with enhanced metabolic stability and receptor selectivity.
What Is a Circular Peptide?
A circular (head-to-tail cyclic) peptide has its N-terminus covalently linked to its C-terminus through an amide bond, creating a continuous backbone ring with no free termini. This topology eliminates exopeptidase attack, restricts conformational flexibility, and often dramatically increases stability and membrane permeability.
Examples
- Cyclosporine A: 11-residue N-methylated cyclic peptide. 30% oral bioavailability
- Cyclotides: Plant-derived cyclic peptides with 3 disulfides (cystine knot). Exceptional stability
- Sunflower trypsin inhibitor (SFTI-1): 14-residue cyclic peptide. Scaffold for drug design
Frequently Asked Questions
What is Circular Peptide?
A peptide in which the N-terminus and C-terminus are joined by a peptide bond, creating a closed ring with enhanced metabolic stability and receptor selectivity.
Why is Circular Peptide important in peptide research?
Circular Peptide is a fundamental concept in structure 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.
Authority Sources
- Circular Peptide on Wikipedia
- Search Circular Peptide on PubChem (NIH)
- Research articles on ScienceDirect