Glossary · 2026-09-24
Scientific lead: Alice Kay, Ph.D.
Molecular weight of a research peptide
Molecular weight, on a peptide paperwork line, is the mass calculated for one named species. Free peptide, an acetate salt, and a trifluoroacetate salt do not share that number. Average mass and monoisotopic mass are also different calculations. The report should say which one it compared with the observed ion.
A catalogue page may cite an approximate free-peptide mass for a defined sequence, as the pentadecapeptide note does for BPC-157. That sentence is not the mass on a later lot. Confirm the figure on the PDF. See the reading guide and pentadecapeptide. Research use only.
Frequently asked questions
- Is the milligram size on the shop URL a molecular weight?
- No. A 10 mg catalogue size is a labelled fill. Molecular weight is a mass per molecule for a stated species, usually in daltons.
- What if the PDF does not say average or monoisotopic?
- Do not guess. Quote the number that is printed and note that the calculation basis was not stated.
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.