Important dilution note: Cloudiness after dilution is most commonly associated with non-pharmaceutical-grade dilution solution. Cloudy product concerns are not eligible for refund unless Pfizer pharmaceutical-grade dilution solution was used.

Vial Size: 3ml

Grade: 4493 (refers to the ~4493 g/mol free-base form; see Molecular Weight below)

Form: Lyophilized white to off-white powder, typically supplied as the TFA (trifluoroacetate) salt

CAS Number: 154947-66-7 — unlike vendor-designated research peptides, LL-37 carries a consistently assigned CAS registry number in authoritative chemical databases. Some listings for fragments, scrambled controls, or D-amino acid analogues (e.g., D-LL-37, LL-37 (17–29)/KR-12) use different identifiers; confirm the CAS matches the full-length parent peptide before ordering.

Chemical Name: Cathelicidin antimicrobial peptide LL-37 — the mature, biologically active C-terminal 37-residue fragment released by proteinase-3 cleavage from the hCAP18 precursor (the sole human cathelicidin, encoded by the CAMP gene). Named for its two N-terminal leucine residues and 37-residue length.

Synonyms: Cathelicidin LL-37; hCAP-18(134–170); CAMP fragment; FALL-39/FALL-36 (precursor-length variants, not identical to LL-37); CRAMP (murine ortholog — related but distinct, do not substitute)

Sequence: H-Leu-Leu-Gly-Asp-Phe-Phe-Arg-Lys-Ser-Lys-Glu-Lys-Ile-Gly-Lys-Glu-Phe-Lys-Arg-Ile-Val-Gln-Arg-Ile-Lys-Asp-Phe-Leu-Arg-Asn-Leu-Val-Pro-Arg-Thr-Glu-Ser-OH — commonly written LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES. A 37-residue, cationic (net charge ~+6 at physiological pH), amphipathic α-helical peptide. Free acid C-terminus is standard; amidated variants exist and behave differently in assay.

Molecular Formula: C₂₀₅H₃₄₀N₆₀O₅₃ (free base). Note that as-shipped material is usually a TFA salt, so gravimetric mass will exceed peptide content — expect roughly 70–85% net peptide by weight depending on counterion load. Check the COA for peptide content by AAA or nitrogen analysis if you are dosing by mass in quantitative assays.

Molecular Weight: ~4493.3 g/mol (monoisotopic ~4490.2). Salt form adds meaningfully to apparent weight.

Purity: ≥95% (HPLC) typical; ≥98% available — see batch COA. Long cationic peptides are prone to deletion sequences during synthesis, so MS confirmation on the COA matters more here than with short peptides.

Storage Conditions: Store lyophilized powder at −20°C, desiccated and protected from light. Reconstituted stock is best aliquoted and held at −80°C; avoid repeated freeze-thaw. Working solutions degrade in solution and are prone to adsorptive loss.

Solubility: Soluble in sterile water and in dilute acetic acid (0.01–0.1%); also soluble in DMSO. Handling caution: LL-37 adsorbs strongly to glass and standard polypropylene, and aggregates in high-ionic-strength or phosphate-containing buffers — apparent loss of activity is frequently a handling artifact rather than a product defect. Low-binding tubes and acidified aqueous stocks are the usual mitigations.

Certificate of Analysis: Available for all batches (verify with individual supplier).

For research and laboratory use only. Not for human or animal consumption. This product has not been evaluated by the FDA and is not intended to diagnose, treat, cure, or prevent any disease or condition. For use by qualified research professionals only.