Are catalogue sequences written from the N-terminus?

Yes. The residue order on these pages starts at the N-terminus. Confirm any modification of that end on the lot file, not from the product title.

Does the N-terminus decide purity?

No. It is a structural end. Purity is the chromatographic figure when the report includes one.

Glossary · 2026-09-24

Scientific lead: Alice Kay, Ph.D.

N-terminus of a peptide chain

The N-terminus is the end of a peptide chain that carries the free amine, unless a report states that the end is blocked or otherwise modified. Residue strings on this site are written from that end. Epithalon's catalogue sequence starts at alanine. BPC-157's published string starts at glycine. Reversing a string would describe a different peptide.

The other end is the C-terminus. A blocked N-terminus changes the mass a laboratory should calculate. Do not add that modification unless the lot file states it. Sequence notation is in the sequence term and in the structure note. Research use only.

Frequently asked questions

Are catalogue sequences written from the N-terminus?: Yes. The residue order on these pages starts at the N-terminus. Confirm any modification of that end on the lot file, not from the product title.
Does the N-terminus decide purity?: No. It is a structural end. Purity is the chromatographic figure when the report includes one.

Research use only. BlueNex Labs does not provide medical or veterinary advice. Confirm your institution’s policies before purchase. How a comparison or class note is checked sits on documentation standards. The biochemist of record is Alice Kay, Ph.D.