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Antimicrobial peptide

Cecropin

Cecropins are antimicrobial peptides first isolated from the hemolymph of the cecropia moth.

By The Peptides Codex Editorial TeamIndividual review date not recorded

Page data last changed: . Chemistry registry snapshot: . Registry refreshes and identity assessments are separate from scientific content review.

Length
n/a
Class
Antimicrobial peptide
Function
Insect host-defense peptides (research)
Context
Antimicrobial-peptide research (not an approved drug)

The insect AMPs that first defined how cecropins lyse both Gram-positive and Gram-negative bacteria.

Also known as: cecropin A · cecropin B

Part of the Foundational & therapeutic peptides cluster

Overview

Cecropins are antimicrobial peptides first isolated from the hemolymph of the cecropia moth. Roughly 31-37 residues long, they form amphipathic alpha-helices and lyse both Gram-positive and Gram-negative bacterial membranes. As a cornerstone of insect innate immunity, they are widely studied research peptides rather than approved drugs.

Source & context

Biological / chemical source: Insect hemolymph (originally the cecropia moth, Hyalophora cecropia)

Primary research or clinical context: Antimicrobial-peptide research (not an approved drug)

Insect innate immunity

Cecropins A, B and D are produced by insects such as Hyalophora cecropia in response to bacterial infection. Their two-helix, amphipathic structure with an AGP hinge lets them permeabilize bacterial membranes, forming a core part of the insect innate immune response.

Hybrids and research use

Cecropin sequences are frequently fused with fragments of melittin to make cecropin-melittin hybrids used to probe membrane selectivity. Cecropins are investigational research peptides here; nothing on this page is a treatment claim.

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
Cecropin (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

Molecular formula
C184H313N53O46
Average reference mass
≈ 4,004
Identifiers

Chemistry values: PubChem · fetched 2026-10-01.

Concentration math

Cecropin — 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: Cecropin (source record; form not independently established)Average reference mass: 4,004 Da

Syringe graduation
Solution concentration
5 mg/mL5,000 mcg/mL
mcg

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.

Open the Cecropin calculator on its own page →

FAQ about Cecropin

What is Cecropin?+

Cecropins are antimicrobial peptides first isolated from the hemolymph of the cecropia moth. Roughly 31-37 residues long, they form amphipathic alpha-helices and lyse both Gram-positive and Gram-negative bacterial membranes. As a cornerstone of insect innate immunity, they are widely studied research peptides rather than approved drugs.

What Canadian product status is recorded for Cecropin?+

Canadian product status for Cecropin 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 Cecropin?+

Cecropin is not a classic amino-acid chain peptide in the same sense; see the profile for classification details.

Related peptides

Nesfatin-1
Neuropeptide / metabolic peptide
Nesfatin-1 is a peptide cleaved from the precursor protein nucleobindin-2 (NUCB2), produced in the hypothalamus and in peripheral tissues. It is studied as a satiety-associated signal in appetite and energy-balance research, and is a frequent topic in metabolic neuropeptide literature.
Bombesin
Neuropeptide
Bombesin is a 14-amino-acid peptide first isolated from amphibian skin that gave its name to a family of mammalian receptors. It is widely used as a research tool in appetite and receptor-biology studies.
Nociceptin
Neuropeptide
Nociceptin (orphanin FQ) is a 17-amino-acid neuropeptide that binds the NOP receptor, a member of the opioid receptor family. It is studied for its complex roles in pain processing, mood, and stress.
P21
Research peptide
P21 (P021) is a synthetic peptide designed as a mimetic of an active region of ciliary neurotrophic factor (CNTF). It has been studied in animal models of neurogenesis and cognitive aging and is not authorized as a medicine by Health Canada.

References & further reading

  1. 1.Lee et al. (2015). Anti-inflammatory activities of cecropin A and its mechanism of action. Arch Insect Biochem Physiol
  2. 2.Park et al. (2021). Expression of Antimicrobial Peptide (AMP), Cecropin B, in a Fused Form to SUMO Tag With or Without Three-Glycine Linker in Escherichia coli and Evaluation of Bacteriolytic Activity of the Purified AMP. Probiotics Antimicrob Proteins
  3. 3.Wang et al. (2018). A novel cecropin B-derived peptide with antibacterial and potential anti-inflammatory properties. PeerJ
  4. 4.Yuan et al. (2024). Interaction of Cecropin A (1-7) Analogs with DNA Analyzed by Multi-spectroscopic Methods. Protein J
  5. 5.Cho et al. (2024). Unveiling the mechanism of bactericidal activity of a cecropin A-fused endolysin LNT113. Int J Biol Macromol
  6. 6.Tian et al. (2024). Antibacterial mechanism and structure-activity relationships of Bombyx mori cecropin A. Insect Mol Biol
  7. 7.Zhao et al. (2024). Cecropin A Alleviates LPS-Induced Oxidative Stress and Apoptosis of Bovine Endometrial Epithelial Cells. Animals (Basel)
  8. 8.Ji et al. (2017). Efficient biosynthesis of a Cecropin A-melittin mutant in Bacillus subtilis WB700. Sci Rep
  9. 9.IJMS — Insect Cecropins, Antimicrobial Peptides with Potential Therapeutic Applications
  10. 10.Wikipedia — Cecropin
Disclaimer: Educational content only. Not medical advice. Not instructions for human use. Research peptides and unapproved products may be restricted or illegal to market for human consumption in your jurisdiction. Consult qualified professionals and applicable law.
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