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A 15-residue peptide with alternating L- and D-amino acids whose dimers form textbook ion channels.
Also known as: gramicidin D · gramicidin A
Part of the Foundational & therapeutic peptides cluster
Overview
Gramicidin is a 15-residue linear peptide antibiotic from the soil bacterium Brevibacillus brevis, notable for alternating L- and D-amino acids. Two molecules assemble head-to-head into a beta-helical channel that lets monovalent cations flood across bacterial membranes, collapsing their ion gradients. It is used topically, often with polymyxin B or neomycin. This page is educational and not medical advice.
Source & context
Biological / chemical source: Soil bacterium Brevibacillus brevis (formerly Bacillus brevis)
Primary research or clinical context: Topical antibiotic (approved for external use) and a classic ion-channel model
Channel-forming mechanism
Gramicidin's alternating L/D sequence lets it fold into a single-stranded beta-helix; two such helices join end-to-end to span the membrane. The resulting pore conducts Na+, K+ and H+, dissipating the electrochemical gradients bacteria need to survive. This makes it a foundational model system in ion-channel biophysics.
Clinical use
Because it is toxic if absorbed systemically, gramicidin is limited to topical products such as antibiotic eye drops, throat lozenges and skin ointments, frequently combined with polymyxin B and neomycin. Selective toxicity toward bacteria at low concentrations underlies these external formulations.
Structure & chemistry
Molecular identity & reference confidence
Source-supported reference
Reference values are taken from the cited molecular record or curated profile. A database match is not independent laboratory verification; modifications, counter-ions, and formulations can change the measured mass.
- Molecular form
- Gramicidin (source record; form not independently established)
- Species
- Not established by this molecular identity audit
- Termini (N / C)
- Not specified / Not specified
Average reference mass
Reference policy updated: 2026-10-05
- PubChem molecular record · 2026-10-01
- Molecular formula
- C99H140N20O17
- Average reference mass
- ≈ 1,882.3
- PubChem CID: 16130140
- CAS RN: 2954858-28-5
- UNII: 5IE62321P4
Chemistry values: PubChem · fetched 2026-10-01.
Clinical development snapshot
ClinicalTrials.gov lists 10 registered studies with “Gramicidin” as an intervention (snapshot 2026-09-06). A registry footprint is not evidence of efficacy or approval.
| NCT | Title | Phase | Status | Updated |
|---|---|---|---|---|
| NCT07702474 | Efficacy of 5% Chitosan Nanoparticle Paste in the Treatment of Recurrent Aphthous Stomatitis | Phase 2 | completed | 2026-07-14 |
| NCT06859281 | Safety, Tolerability, and Pharmacokinetic Profile of Grammidin, a Metered Dose Topical Spray in Healthy Volunt | Phase 1 | recruiting | 2025-07-10 |
| NCT06843018 | Study to Evaluate the Efficacy and Safety of Different Doses of Graminidin With Anesthetic, a Metered Dose Top | Phase 2 | recruiting | 2025-07-10 |
| NCT06857890 | Safety, Tolerability, and Pharmacokinetic Profile of Grammidin With Anesthetic, a Metered Dose Topical Spray i | Phase 1 | recruiting | 2025-07-10 |
| NCT04323475 | Phage Therapy for the Prevention and Treatment of Wound Infections in Burned Patients | Phase 1 | unknown | 2021-12-22 |
| NCT01950598 | Frozen Versus Fresh Corneal Carriers for the Boston KPro Type I Donor Carriers | Not applicable | completed | 2021-01-28 |
Gramicidin — reconstitution calculator
Enter how much peptide is in the vial and how much diluent (e.g. bacteriostatic water) is added. The tool returns the resulting solution concentration — and, for any amount you type, the volume it corresponds to. This is educational arithmetic, not a dosing recommendation.
Reference form: Gramicidin (source record; form not independently established)Average reference mass: 1,882.3 Da
Enter an amount to see the volume it corresponds to.
Educational concentration mathematics only. This tool does not recommend a dose, amount, or protocol, and nothing here is medical advice. Many peptides are not authorized by Health Canada for human use — see our reconstitution and bacteriostatic-water guides for context.
Change log
Dated observations from the data pipeline (registry flags, trial footprints, identifiers) and editorial reviews of this profile.
- ChemistryPubChem formula updated to C99H140N20O17.
FAQ about Gramicidin
What is Gramicidin?+
Gramicidin is a 15-residue linear peptide antibiotic from the soil bacterium Brevibacillus brevis, notable for alternating L- and D-amino acids. Two molecules assemble head-to-head into a beta-helical channel that lets monovalent cations flood across bacterial membranes, collapsing their ion gradients. It is used topically, often with polymyxin B or neomycin. This page is educational and not medical advice.
What Canadian product status is recorded for Gramicidin?+
Canadian product status for Gramicidin has not been verified in this profile. No verified record here does not mean no authorization exists. Status depends on the product, formulation and use; consult Health Canada's product records.
What is the typical length of Gramicidin?+
Gramicidin is commonly described as approximately 15 amino acids (Linear peptide antibiotic (ion-channel former)).
Related peptides
References & further reading
- 1.Kaman et al. (2022). Gramicidin A is hydrolyzed by a d-stereospecific peptidase produced by Bacillus anthracis. Environ Microbiol Rep
- 2.Kondrashov et al. (2024). Gramicidin A in Asymmetric Lipid Membranes. Biomolecules
- 3.Dibas et al. (1995). Gramicidin D is a potent insulin secretagogue: dependence on extracellular calcium influx. Biochem Biophys Res Commun
- 4.Li et al. (2023). New role of gramicidin A in RIG-I-like receptors-mediated IFN signalling. Immunology
- 5.Urry et al. (1971). The gramicidin A transmembrane channel: characteristics of head-to-head dimerized (L,D) helices. Proc Natl Acad Sci U S A
- 6.Stankovic et al. (1990). Purification of gramicidin A. Anal Biochem
- 7.Cornell (1987). Gramicidin A--phospholipid model systems. J Bioenerg Biomembr
- 8.Jadhav et al. (2017). Bioactivity of topologically confined gramicidin A dimers. Bioorg Med Chem
- 9.PubChem — compound summary for Gramicidin (CID 16170150)
- 10.Wikipedia — Gramicidin