Peptide product profiles often include an amino acid sequence, molecular formula, and molecular weight. These fields describe related aspects of identity, but they are not interchangeable.
Amino acid sequence
The sequence lists residues in order, generally from the N-terminus to the C-terminus. It communicates the primary structure of the peptide. Modified residues, terminal groups, linkers, or attached moieties may be shown with brackets, abbreviations, or notes.
Molecular formula
The molecular formula reports the total number of each element in the stated molecular form. It reflects more than the one-letter amino acid sequence when the compound includes terminal modifications, salts, conjugates, cyclization, or other structural features.
Molecular weight
Molecular weight is the calculated or reported mass of the molecule, usually expressed in daltons. A modified peptide can have a molecular weight that differs substantially from an unmodified sequence with a similar residue count.
Read all three together
A strong product record keeps the sequence, modification notes, formula, and molecular weight consistent. If a field appears incomplete or ambiguous, researchers should request clarification rather than infer missing structural details.
These identifiers support educational and laboratory review. They do not establish clinical suitability, safety, efficacy, or approval for human or veterinary use.