Peptides, explained plainly.
Short, factual pieces on the material and the paperwork: what peptides are, how they are made, tested, packed and stored, and what the label means.
Basics
Start here: what a peptide is, how amino acids join, and what the label says.
What are peptides? A plain definition
A peptide is a short chain of amino acids joined by peptide bonds. What that means chemically, how peptides differ from proteins, and how one is described.
ReadBasics4 min readThe peptide bond: how amino acids join
A peptide bond is the amide link between the carboxyl of one amino acid and the amino group of the next: how it forms, why it is flat, and how it breaks.
ReadBasics4 min readTypes of peptides: by length, shape and modification
Types of peptides by length, shape (linear or cyclic) and chemical modification, with residue counts from PubChem records for catalogue examples.
ReadBasics3 min readReading a Solara label
Every Solara vial carries five things: the compound name, the quantity in milligrams, the form, an expiry date and the research-use line. What each one means.
ReadMaterial
What the powder is, how it is made, packed and stored.
What lyophilized means
Lyophilized means freeze-dried: ice removed under vacuum, leaving a porous cake. How the three stages work, and what residual moisture is.
ReadMaterial3 min readHow synthetic peptides are made
Most research peptides are built by solid-phase synthesis, cleaved from the resin, purified by HPLC and freeze-dried. Chain length limits crude purity.
ReadMaterial3 min readHow to store peptides: storage and transit of lyophilized powder
Why a sealed, dry peptide changes slowly over days at room temperature, what speeds that change, and what −20 °C storage slows.
ReadMaterial4 min readPeptide degradation: deamidation, oxidation and cleavage
The chemical routes of peptide degradation (deamidation, oxidation, cleavage, cyclization) and the mass and HPLC signature each one leaves.
ReadMaterial3 min readLight and peptides
Which residues and metal centres absorb light, how ICH Q1B tests photostability, and why a lyophilized powder is kept protected from light.
ReadMaterial3 min readThe vial: glass, stopper and seal
A lyophilized peptide vial is typically Type I borosilicate glass, a freeze-drying stopper and an aluminium crimp seal. What each part does.
ReadAnalysis
What the tests measure, and what they do not.
What HPLC purity measures
An HPLC purity figure is the main peak's share of integrated UV peak area, usually near 214 nm: what it counts, what it misses, and why the method matters.
ReadAnalysis4 min readConfirming identity by mass spectrometry
How mass spectrometry tests whether a peptide has the mass its sequence predicts, and what a matching mass still leaves open.
ReadAnalysis4 min readKarl Fischer titration: measuring water in a peptide powder
Karl Fischer titration measures water by its reaction with iodine. How coulometric and volumetric forms work, and why loss on drying gives a different figure.
ReadSpecification
What the numbers and the names mean.
Purity versus net peptide content
A figure of 99% by HPLC describes the peptide fraction of a powder, not the powder. Net peptide content is a separate measurement that sets molar quantity.
ReadSpecification3 min readHow research peptides are named
Code numbers, fragment ranges, suffixes and prefixes each state something specific about a peptide, and similar names can mean different molecules.
ReadSpecification4 min readHow a peptide sequence is written
A peptide sequence runs from the N-terminus to the C-terminus in three-letter or one-letter code, with marks such as Ac- and -NH2 for modified ends.
ReadSpecification4 min readD- and L-amino acids in synthetic peptides
D-amino acids are the mirror-image forms of the L-amino acids in proteins. How D-residues arise in a synthetic peptide, and how chiral purity is measured.
ReadSpecification4 min readCopper peptides: the chemistry of GHK-Cu
A copper peptide such as GHK-Cu is a peptide holding a Cu(II) ion: how glycyl-histidyl-lysine binds copper, why it is blue, and PubChem reference values.
ReadPaperwork
Grades, certificates, status and how to judge a supplier.
What a certificate of analysis shows
A certificate of analysis ties one lot to the tests run on it. What a peptide COA should state, what makes it checkable, and what it cannot establish.
ReadPaperwork3 min readResearch grade versus pharmaceutical grade
Research grade and pharmaceutical grade describe different systems of control and documentation, not two points on one purity scale.
ReadReady when you are.
Thirty-one compounds and blends, labelled plainly and shipped from Canada.