Reading Peptide Specifications: Sequence, CAS Number and Molecular Weight
June 13, 2026 · by Administrator
Every product page includes a technical data sheet. Understanding those fields helps you confirm you are looking at the right compound.
Amino-acid sequence
The sequence is the order of amino acids, often written in one-letter code. It defines the peptide’s identity — two peptides with different sequences are different compounds.
CAS number
A CAS number is a unique identifier assigned to a chemical substance, useful for unambiguous reference across databases and literature.
Molecular formula and weight
The molecular formula lists the atoms in the molecule; the molecular weight is its mass in g/mol. Molecular weight is what mass spectrometry measures to confirm identity.
Definitions for each of these terms are in our peptide glossary.
All products referenced are supplied strictly for laboratory and research use only and are not for human consumption.
For research use only. Not for human consumption. This article is educational and not medical advice.