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LL-37 testing in Canada

Thirty-seven residues, highly charged, and difficult to synthesise cleanly. Purity is a more informative figure here than for almost anything else we test.

$249CAD

Results in about five business days from arrival

Order this test
  • Identity by LC–MS/MS
  • Purity, with the method stated
  • Net peptide content in mg
  • Chromatographic peak data
  • Certificate anyone can verify

Thirty-seven residues, strongly cationic

The only human cathelicidin antimicrobial peptide, 37 residues long and strongly cationic. Its length and charge both work against clean synthesis.

Residues
37
Formula
C205H340N60O53
Mol. weight
4493.0 Da
Also called
Cathelicidin, hCAP-18(134-170)

Why length is the enemy here

Deletion sequences

Thirty-seven coupling steps at slightly less than perfect efficiency produce a population of chains missing one residue, or two, scattered through the sequence. These are not impurities in the usual sense — they are peptides, closely related to the target, and they will be counted as peptide by any method that is not resolving them.

This is where a purity figure earns its keep, and where the method used to obtain it matters more than the number itself.

Charge makes it sticky

A strongly cationic peptide binds to glass, to plastic, and to chromatography media. Recovery losses during handling are real, which means the amount in the vial and the amount that reaches an experiment can differ for reasons that have nothing to do with the vendor.

Endotoxin matters more here

LL-37 is studied for antimicrobial activity, so bacterial endotoxin contamination is not merely a safety question — it directly confounds what the compound is being used to investigate. Why endotoxin is measured separately.

What your certificate reports

  1. Identity — confirmed from precursor-to-product-ion transitions on a triple quadrupole instrument, not inferred from retention time.
  2. Purity — measured at the quantifying transition, with the method named on the report.
  3. Net peptide content — quantified against an external calibration curve and reported as its own figure, in milligrams. Why this is a different number from purity.
  4. Peak data — the chromatographic results behind each figure, printed on the certificate rather than held back.

Common questions

How much sample do you need?

One unopened vial. Detailed posting instructions arrive with your order confirmation, immediately after you pay.

Does it need to be shipped cold?

No. Lyophilised peptides travel safely at room temperature, which is how nearly all samples reach us.

Who actually performs the analysis?

An independent Ontario laboratory. Every certificate we issue names the facility that ran it — we are a testing service, not a laboratory, and we would rather say so than let you find out from the report.

What if the result comes back bad?

You get the result. We do not soften findings, and we do not charge differently depending on what the analysis shows.

Can I verify the certificate is genuine?

Yes. Every certificate carries an identifier that anyone can check against our records, including the vendor you bought from.

Related reading

ExplainedPurity is not contentA vial can be 99% pure and hold a quarter less peptide than the label says.ExplainedWhat endotoxin isAnd why a peptide method will not find it.ExplainedHow labs know what is in a vialMass spectrometry without the jargon, and why weighing beats timing.

Test your ll-37

$249 CAD · about five business days from arrival · never leaves Canada

Order this test