Peptide Research Glossary

A ligand that binds to and activates a receptor under the conditions of an assay or biological system.

An organic molecule with amino and carboxyl functional groups; amino-acid residues join in a defined order to form peptides.

Also: primary sequence

The ordered list of residues in a peptide, normally written from the amino terminus to the carboxyl terminus.

The time required for a measured amount or concentration to decrease by half under specified conditions.

Also: in-vitro

Research performed outside a living organism, such as in a test tube, purified system, or cultured cells.

Also: in-vivo

Research performed in a living organism, usually an animal model when discussed in preclinical peptide literature.

A molecule or ion that binds to another molecular structure, often a receptor, enzyme, or protein.

Also: molecular mass · MW

The mass of a molecule, commonly expressed as relative molecular mass or in daltons for peptide work.

Key term

A molecule made from amino-acid residues connected by peptide bonds.

Also: peptide analog

A molecule designed to resemble a naturally occurring peptide while containing one or more sequence or chemical modifications.

The amide linkage formed between the carboxyl group of one amino acid and the amino group of another.

Key term

A molecular structure, commonly a protein, that can bind a ligand and influence cellular signalling.

Also: RUO · research-use-only

A supplier or label designation indicating that material is provided for research rather than diagnosis, treatment, disease prevention, or human consumption.

Read research-use FAQs

Also: signaling pathway

A connected series of molecular interactions through which a cell receives and processes a signal.

Key term

Also: content assay · net content · peptide content

A method-dependent estimate of how much target compound is present, often reported per container or as a mass fraction.

ICH Q2(R2): Validation of Analytical ProceduresICH Q6A: Specifications and Test Procedures

Also: lot number · batch number

An identifier assigned to material produced or packaged under defined conditions.

The population of viable microorganisms present in or on material before a sterilising step, or measured as a microbial-quality attribute.

FDA: Sterile Drug Products Produced by Aseptic Processing

A sample submitted with some identifying or expected-result information withheld to reduce analytical bias.

Key term

Also: CoA · certificate of analysis · analysis certificate

A document reporting tests, methods, specifications, and results for an identified sample or batch.

ICH Q6A: Specifications and Test ProceduresView published batch reports

A documented record of who collected, possessed, transferred, stored, and submitted a sample.

The plotted detector response produced during a chromatographic separation.

Key term

Also: HPLC purity · area purity · UPLC purity

The proportion of integrated detector response assigned to the target peak under a stated chromatographic method.

ICH Q2(R2): Validation of Analytical ProceduresICH Q6A: Specifications and Test Procedures

Also: report verification · certificate verification

A check that a report is authentic, unaltered, and corresponds to the issuing laboratory’s record.

Open the testing library

Also: salt form · acetate salt · TFA salt · trifluoroacetate

The oppositely charged ion associated with an ionised peptide, such as acetate or trifluoroacetate, and the resulting material form.

Also: heavy metals · heavy-metals screen

Specified elements measured as potential impurities, typically using a method such as ICP–MS or ICP–OES.

ICH Q3D(R2): Elemental Impurities

Key term

Also: bacterial endotoxin · LPS

Bacterial lipopolysaccharide contamination assessed separately from viable microorganisms.

FDA: Pyrogen and Endotoxins Testing Q&A

Key term

Also: high-performance liquid chromatography · high pressure liquid chromatography

High-performance liquid chromatography: a technique that separates sample components before detector measurement.

ICH Q2(R2): Validation of Analytical ProceduresSee HPLC reports in the testing library

Key term

Also: identity · identification

An analysis that provides evidence about whether a sample contains the intended compound.

ICH Q2(R2): Validation of Analytical ProceduresICH Q6A: Specifications and Test Procedures

Also: Janoshik Analytical

A third-party analytical laboratory whose reports can include online verification records.

View published Janoshik reports

Key term

Also: LC-MS · liquid chromatography mass spectrometry

Liquid chromatography–mass spectrometry: separation of sample components followed by measurement of ion mass-to-charge patterns.

ICH Q2(R2): Validation of Analytical Procedures

Also: LOD · detection limit

The lowest amount or concentration that a method can reliably distinguish from background under stated conditions.

ICH Q2(R2): Validation of Analytical Procedures

Also: LOQ · quantitation limit · quantification limit

The lowest amount or concentration that can be quantified with suitable performance under stated method conditions.

ICH Q2(R2): Validation of Analytical Procedures

Also: MALDI-TOF · matrix-assisted laser desorption ionization

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry, a technique used to measure molecular mass patterns.

Also: MS · mass spec

An analytical family of techniques that measures ion mass-to-charge ratios.

ICH Q2(R2): Validation of Analytical Procedures

An accounting of the measured components that contribute to the total mass of a material.

ICH Q6A: Specifications and Test Procedures

Also: uncertainty · expanded uncertainty

A quantified expression of the dispersion reasonably associated with a measured result.

ICH Q2(R2): Validation of Analytical Procedures

Also: TAMC · TYMC · microbial count · microbial limits

Counts used to estimate total aerobic microorganisms and total combined yeasts and moulds under a stated method.

Key term

The proportion attributed to the target by a stated analytical method and reporting basis.

ICH Q2(R2): Validation of Analytical ProceduresICH Q6A: Specifications and Test Procedures

Also: analytical standard · calibration standard

A well-characterised material used as a comparison or calibration point in an analytical method.

ICH Q2(R2): Validation of Analytical Procedures

Volatile organic chemicals that can remain from synthesis, purification, or manufacturing processes.

ICH Q3C(R8): Residual Solvents

A documented rule for how many units are selected, from where, by whom, and for which tests.

A predefined acceptance criterion or set of criteria for a material or test result.

ICH Q6A: Specifications and Test Procedures

Key term

Also: sterility

A test for viable microorganisms under defined conditions.

FDA: Sterile Drug Products Produced by Aseptic Processing

Key term

Also: independent testing · external laboratory

Analysis performed by an organisation separate from the supplier or manufacturer.

View published third-party reports

Key term

The ability to follow a material, sample, measurement, or result through documented identifiers and records.

See how reports map to batches

Also: ultra-performance liquid chromatography · UHPLC

Ultra-performance liquid chromatography, a form of liquid chromatography using equipment and columns designed for high-efficiency separations.

ICH Q2(R2): Validation of Analytical Procedures

Also: moisture content

The amount of water present in a material, measured separately from chromatographic area purity.

ICH Q6A: Specifications and Test Procedures

Also: BAC water · bacteriostatic water for injection

Sterile water containing an antimicrobial preservative, commonly 0.9% benzyl alcohol when labelled accordingly.

View bacteriostatic-water information

Temperature-controlled storage and transport across the documented handling journey.

Read delivery information

Key term

Also: mg/mL · mass concentration

The amount of a substance per unit volume, such as milligrams per millilitre.

Open the reconstitution calculator

A liquid used to dissolve or dilute a material.

A formulation component other than the target compound, used for properties such as stability, solubility, pH, or tonicity.

Also: lyophilization · freeze-drying · freeze drying

Freeze-drying: removal of water from frozen material by sublimation under reduced pressure.

Also: lyophilized vial · lyo vial

A sealed vial containing freeze-dried material rather than a prepared liquid solution.

A logarithmic measure related to hydrogen-ion activity in an aqueous solution.

Key term

Adding a specified diluent to dry material to prepare a solution of calculated nominal concentration.

Use the concentration calculator

The ability of a material to retain specified attributes over time under stated conditions.

Water prepared to meet a sterility standard and generally lacking a bacteriostatic preservative.

The documented temperature, light, humidity, orientation, and time limits for keeping a material.

A period when material is outside its specified storage range.

Also: syringe unit · U100 · U-100

On a U-100 insulin syringe, one graduation labelled as a unit corresponds to 0.01 mL.

A small sealed container used for dry or liquid laboratory material.

Also: AOD9604 · hGH fragment 176-191

A synthetic, modified peptide based on the C-terminal region of human growth hormone and studied as a distinct research compound.

Heffernan et al., AOD9604 review (PubMed)View AOD-9604 product information

Key term

Also: BPC157 · Body Protection Compound 157

A synthetic 15-residue peptide used primarily in preclinical and laboratory research.

Sikiric et al., Frontiers in Pharmacology (PubMed)View BPC-157 product information

Key term

Also: CJC1295 no DAC · CJC-1295 no DAC · Modified GRF 1-29 · Mod GRF 1-29

A marketplace name often used for Modified GRF (1–29), a stabilised growth-hormone-releasing-hormone fragment without the albumin-binding DAC group.

Teichman et al., CJC-1295 study (PubMed)View CJC-1295 (no DAC) + Ipamorelin product information

Key term

Also: GHK Cu · Copper tripeptide-1 · Copper peptide GHK-Cu

The copper(II) complex of the tripeptide glycyl-L-histidyl-L-lysine, also called copper tripeptide-1.

Pickart et al., GHK-Cu review (PubMed)View GHK-Cu product information

Also: glucose-dependent insulinotropic polypeptide · gastric inhibitory polypeptide

Glucose-dependent insulinotropic polypeptide, an endogenous peptide hormone that signals through the GIP receptor.

IUPHAR/BPS Guide to Pharmacology: GIP receptor

Also: GLP1 · glucagon-like peptide 1

Glucagon-like peptide-1, an endogenous peptide hormone that signals through the GLP-1 receptor.

IUPHAR/BPS Guide to Pharmacology: GLP-1 receptor

Also: GLOW · GHK-Cu BPC-157 TB-500 blend

A ProPeptide catalogue blend name for a fixed combination of GHK-Cu, BPC-157, and TB-500; it is not a single molecular entity.

View GLOW blend composition

Also: GCGR · glucagon receptor 1

A class B G-protein-coupled receptor activated by glucagon and commonly abbreviated GCGR.

IUPHAR/BPS Guide to Pharmacology: glucagon receptor

Key term

Also: NNC 26-0161

A synthetic pentapeptide characterised as an agonist at the growth-hormone secretagogue receptor in experimental systems.

Raun et al., European Journal of Endocrinology (PubMed)View CJC-1295 (no DAC) + Ipamorelin product information

Also: Lys-Pro-Val · lysine proline valine

The tripeptide lysine–proline–valine, corresponding to the C-terminal three residues of α-melanocyte-stimulating hormone.

Dalmasso et al., KPV study (PubMed)View KPV product information

Key term

Also: MOTSc · MOTS C · mitochondrial open reading frame of the 12S rRNA-c

A 16-amino-acid mitochondrial-derived peptide encoded within the mitochondrial 12S rRNA region.

Lee et al., Cell Metabolism (PubMed)View MOTS-C product information

Also: PT141 · PT 141 · bremelanotide

A synthetic cyclic peptide and melanocortin-receptor agonist known by the development code PT-141 and the generic name bremelanotide.

FDA Drugs@FDA: bremelanotideView PT-141 product information

Key term

Also: LY3437943 · LY 3437943 · triple receptor agonist

An investigational synthetic peptide engineered for agonist activity at GIP, GLP-1, and glucagon receptors.

Coskun et al., retatrutide discovery paper (PubMed)ClinicalTrials.gov: NCT06383390View Retatrutide product information

Key term

Also: SS31 · SS 31 · elamipretide · MTP-131 · MTP131 · Bendavia

A synthetic aromatic-cationic tetrapeptide known in research literature as SS-31, MTP-131, or elamipretide.

FDA: accelerated approval of elamipretideView SS-31 product information

Key term

Also: TB500 · TB 500

A commercial research designation used for synthetic materials described as related to thymosin beta-4.

FDA: safety information for TB-500 fragmentGoldstein et al., Thymosin beta-4 review (PubMed)View TB-500 product information

Key term

Also: TH9507 · tesamorelin acetate

A stabilised synthetic analogue of growth-hormone-releasing hormone that acts at the GHRH receptor.

FDA Drugs@FDA: tesamorelinView Tesamorelin product information

Key term

Also: Tβ4 · T beta 4 · thymosin β4 · TMSB4X

A naturally occurring 43-amino-acid peptide, commonly abbreviated Tβ4, with actin-binding functions studied across many model systems.

Goldstein et al., Thymosin beta-4 review (PubMed)

Key term

Also: LY3298176 · LY 3298176 · dual GIP GLP-1 agonist

A synthetic peptide agonist at the GIP and GLP-1 receptors.

FDA Drugs@FDA: tirzepatideView Tirzepatide product information

Key term

Also: tri-agonist · triple receptor agonist

A compound designed to activate three specified receptor types.

Coskun et al., retatrutide discovery paper (PubMed)