Peptide research glossary
Updated
In short
This glossary defines the terms that recur across peptide product listings, certificates of analysis and research literature — from lyophilisation and HPLC purity through to receptor classes such as GHS-R1a and structural terms such as retro-inverso.
Terms are grouped by where you are most likely to meet them: on a vial label, on a certificate of analysis, or in the literature describing a compound.
On the vial and the product page
| Term | Definition |
|---|---|
| Lyophilized | Freeze-dried. Water is removed under vacuum from the frozen state, leaving a solid cake that is stable for long-term storage and reconstituted before use. |
| Reconstitution | Dissolving lyophilized powder back into solution, usually with bacteriostatic or sterile water. |
| Bacteriostatic water | Sterile water containing a preservative, typically benzyl alcohol, which limits microbial growth in a vial drawn from more than once. |
| Fill size | The mass of lyophilized peptide in the vial, e.g. 5 mg. It is not a concentration — that depends on how much solvent is added at reconstitution. |
| Fill weight | The mass of peptide in the vial. It sets the working concentration together with the volume of solvent added. |
| SKU | The catalogue identifier for a specific product listing, distinct from a batch or lot number. |
On a certificate of analysis
| Term | Definition |
|---|---|
| HPLC | High-performance liquid chromatography. Separates a sample into its components; the target's share of total peak area is reported as purity. |
| Mass spectrometry (MS) | Confirms molecular identity by measuring mass-to-charge ratio. The observed mass should match the theoretical mass for the stated sequence. |
| Batch / lot number | Identifies one manufacturing run. A COA applies only to the batch whose number it carries. |
| Peptide content | The proportion of the vial's total mass that is peptide, as opposed to water, counter-ion and residual solvent. Distinct from chromatographic purity. |
| Counter-ion | The salt form a synthesised peptide is isolated as, commonly acetate or trifluoroacetate. It contributes to total mass. |
In the literature
| Term | Definition |
|---|---|
| Secretagogue | A compound that triggers secretion. In this catalogue it refers to growth hormone secretagogues acting at the ghrelin receptor. |
| GHS-R1a | The ghrelin receptor — the target of Ipamorelin, GHRP-2, GHRP-6 and Hexarelin. |
| GHRH | Growth hormone releasing hormone; the parent of Sermorelin, Mod GRF 1-29, CJC-1295 and Tesamorelin. |
| DAC | Drug affinity complex — a linker that binds serum albumin covalently, extending a peptide's circulating half-life. |
| DPP-IV | Dipeptidyl peptidase IV, an enzyme that cleaves peptides at a specific N-terminal motif. Many analogues exist specifically to resist it. |
| Retro-inverso | A peptide rebuilt from D-amino acids in reversed sequence. It presents a similar side-chain arrangement while being essentially invisible to proteases. |
| Ligand trap | A soluble receptor fragment that binds a signalling molecule before it reaches its receptor, reducing available ligand rather than blocking the receptor. |
| Bioregulator | In this catalogue, the Khavinson series of very short peptides, each associated in the Russian literature with a specific tissue. |
| PEGylation | Covalent attachment of polyethylene glycol to increase stability and size. Molar calculations must use the conjugate mass. |
| Lyophilisate / cake | The solid mass of freeze-dried peptide sitting at the bottom of the vial. |
Frequently asked questions
- What does lyophilized mean?
- Freeze-dried. The peptide is frozen and the water removed under vacuum, leaving a solid cake that stores well and is dissolved in solvent before use.
- What does fill size mean on a peptide vial?
- The mass of lyophilized peptide in the vial — 5 mg, 10 mg and so on. It is not a concentration: the working strength depends on how much solvent is added at reconstitution, so one fill size can be prepared many ways.
- What is the difference between a SKU and a batch number?
- A SKU identifies a product listing in the catalogue. A batch or lot number identifies one specific manufacturing run of that product, and is what a certificate of analysis refers to.
All products referenced are sold for research, laboratory, or analytical purposes only, and are not for human consumption.