Peptide reference materials are identified by a name, an amino-acid sequence, and a molecular mass. Understanding how these relate makes it easier to cross-reference a product against its Certificate of Analysis and published literature.
Names and sequences
A peptide's name may be a research code, a descriptive abbreviation, or a laboratory designation. Behind the name is a defined sequence of amino acids. The sequence determines the theoretical molecular mass, which mass spectrometry measures to confirm identity on a COA.
Modifications
Documentation often notes modifications such as acetylation or amidation (for example, an N-acetyl or amidated form). These modifications change the molecule and its theoretical mass, so the modified form is documented distinctly from the unmodified peptide.
Blends
A blended reference material contains more than one peptide in defined amounts, documented as a ratio — for example, a 10 mg / 10 mg blend contains 10 mg of each component. When reconstituting a blend, the concentration equation applies to each component separately based on its stated mass in the vial.