Reference
Peptide lexicon.
A plain-language reference to the terms used across peptide research — from reconstitution and purity testing to receptors, analogues and the compounds in our catalogue.
83 terms
A
- Agonist
- A molecule that binds to and activates a receptor, producing a biological response similar to that of the receptor's natural signaling molecule. In pharmacology, agonists are characterized by their affinity for the receptor and their efficacy in eliciting a response.See also: Receptor, Antagonist, Ligand
- Aliquot
- An aliquot is a measured portion of a larger sample or solution divided into smaller units, typically for separate storage or analysis. Dividing a reconstituted solution into aliquots limits repeated exposure of the whole batch to handling and freeze-thaw cycles.
- Amino acid
- An amino acid is an organic molecule containing an amino group, a carboxyl group and a side chain that defines its identity. Amino acids are the fundamental building blocks from which peptides and proteins are assembled.See also: Peptide, Residue
- Amylin
- A peptide hormone co-secreted with insulin by the beta cells of the pancreas that is studied for its role in glucose regulation, gastric emptying, and satiety signaling. It is a subject of research on metabolic and appetite pathways.
- Analogue
- An analogue is a compound whose structure is deliberately modified from a reference molecule, for example by substituting, adding or removing amino acid residues. Analogues are studied to explore how structural changes affect stability, binding and activity.See also: Half-life, AgonistRelated article →
B
- Bacteriostatic water
- Bacteriostatic water is sterile water containing a small proportion of benzyl alcohol, an agent that inhibits the growth of bacteria. This preservative allows the liquid to be used for reconstituting and storing solutions across multiple withdrawals in laboratory settings.See also: Sterile water, ReconstitutionRelated article →
- Batch
- A batch is a specific quantity of material produced in a single manufacturing run under uniform conditions, so that all units within it are expected to share the same characteristics. Grouping production into batches allows quality testing and traceability to be applied to a defined, identifiable quantity of product.
- BPC-157
- BPC-157 is a synthetic pentadecapeptide whose sequence is derived from a protein found in gastric juice. It is studied in laboratory models for its investigated roles in cellular repair processes, angiogenesis, and connective tissue biology.Related article →
C
- C-terminus
- The C-terminus is the end of a peptide or protein chain that carries a free carboxyl group. By convention it marks the end of the sequence and is written on the right when the sequence is notated.
- Cagrilintide
- Cagrilintide is a synthetic long-acting analog of the pancreatic hormone amylin. It is investigated in metabolic research for its interaction with amylin and calcitonin receptors and its role in satiety and energy balance signaling.See also: Amylin, SemaglutideRelated article →
- Cardiolipin
- A distinctive phospholipid found predominantly in the inner mitochondrial membrane that plays a structural and functional role in cellular energy production. It is studied in research on mitochondrial biology and bioenergetics.
- Certificate of analysis (COA)
- A certificate of analysis (COA) is a document issued by a laboratory that reports the results of analytical tests performed on a specific batch of material, confirming its identity, purity, and physical characteristics against defined specifications. It typically summarizes methods such as HPLC and mass spectrometry alongside the measured values.See also: HPLC, Mass spectrometry, Purity, BatchRelated article →
- CJC-1295
- CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH) modified to extend its stability. It is studied in endocrine research as a growth hormone secretagogue that acts on GHRH receptors to influence the growth hormone axis.See also: GHRH, Tesamorelin, IpamorelinRelated article →
- Cold chain
- The cold chain is an uninterrupted series of temperature-controlled storage and transport steps that keep a sensitive product within a defined low-temperature range from origin to end use. Maintaining the cold chain helps preserve the stability and integrity of peptides and other temperature-sensitive materials.Related article →
- Concentration
- Concentration is a measure of the amount of a substance present within a given volume of solution, commonly expressed in units such as milligrams per millilitre (mg/mL). Knowing the concentration of a reconstituted peptide solution is essential for accurate quantitative work in the laboratory.
D
- Dead volume
- Dead volume is the small quantity of liquid retained within a syringe, needle hub, or container that cannot be fully expelled or recovered after dispensing. In peptide research, it is a recognized source of material loss and volumetric imprecision during reconstitution and measurement, particularly when handling small volumes of costly solutions.See also: Reconstitution, Insulin unit, Vial
- Dilution
- Dilution is the process of reducing the concentration of a solute in a solution by adding more solvent. In laboratory practice it is used to prepare a solution of lower, precisely known concentration from a more concentrated stock solution.
E
- Endotoxin
- Endotoxins are lipopolysaccharide molecules found in the outer membrane of Gram-negative bacteria and released when the cells break down. They are a common contaminant monitored in laboratory materials because their presence can confound biological experiments, and their levels are typically measured by assays such as the Limulus amebocyte lysate (LAL) test.
F
- Freeze-thaw cycle
- A freeze-thaw cycle is one complete sequence of freezing a sample and then returning it to a liquid state. Repeated freeze-thaw cycles can mechanically and chemically stress dissolved peptides, potentially causing degradation or aggregation, which is why solutions are often aliquoted before freezing.Related article →
G
- GHK-Cu
- GHK-Cu is a copper-binding tripeptide composed of glycine, histidine, and lysine complexed with a copper(II) ion. It is studied in biochemical and dermatological research for its role in copper transport, extracellular matrix signaling, and tissue remodeling.Related article →
- GHRH
- Growth hormone-releasing hormone is a hypothalamic peptide that stimulates the pituitary gland to synthesize and release growth hormone. It is studied in endocrinology research on the regulation of the growth hormone axis.See also: GHRP, Growth hormone secretagogueRelated article →
- GHRP
- Growth hormone-releasing peptides are a family of synthetic peptides that stimulate growth hormone release by acting on the ghrelin/growth hormone secretagogue receptor. They are widely used as tools in laboratory research on the growth hormone axis.See also: GHRH, Growth hormone secretagogueRelated article →
- GIP
- Glucose-dependent insulinotropic polypeptide is an incretin hormone secreted by the small intestine following food intake. It is investigated in metabolic research alongside GLP-1 for its involvement in insulin secretion and energy metabolism.See also: GLP-1, IncretinRelated article →
- GLP-1
- Glucagon-like peptide-1 is an incretin hormone released by intestinal cells in response to nutrient intake. It is widely studied in metabolic research for its role in glucose regulation, insulin signaling, and appetite pathways.See also: GIP, Glucagon, Incretin, AgonistRelated article →
- Glucagon
- A peptide hormone produced by the alpha cells of the pancreas that acts to raise blood glucose levels, opposing the action of insulin. It is a key subject in research on glucose homeostasis and energy metabolism.See also: GLP-1, IncretinRelated article →
- GMP
- Good Manufacturing Practice (GMP) is a system of quality standards and documented procedures that govern the production and control of materials to ensure they are consistently manufactured according to defined specifications. It covers aspects such as facilities, equipment, personnel, and record-keeping.
- Growth hormone secretagogue
- A compound that promotes the secretion of growth hormone from the pituitary gland, typically by activating the growth hormone secretagogue receptor. This category includes ghrelin and various synthetic peptides studied in endocrine research.See also: GHRH, GHRPRelated article →
H
- Half-life
- Half-life is the time required for the quantity or concentration of a substance to decrease to half of its initial value. In biochemical research it is used to characterize how quickly a peptide degrades or is cleared under given conditions.Related article →
- HPLC
- High-performance liquid chromatography (HPLC) is an analytical technique that separates the components of a mixture by passing it, dissolved in a solvent, through a column packed with a stationary phase. It is widely used in peptide research to assess identity and to quantify purity by measuring the relative abundance of the separated peaks.See also: Mass spectrometry, PurityRelated article →
- Hydrolysis
- Hydrolysis is a chemical reaction in which a molecule is cleaved into smaller fragments through the addition of water. In peptides, hydrolysis can break the peptide bonds linking amino acids, and it is one of the pathways by which a peptide in solution may degrade over time.Related article →
I
- In vitro
- In vitro is a Latin term meaning 'in glass' that describes experiments or processes carried out outside a living organism, such as in test tubes, culture dishes, or other controlled laboratory environments. In vitro studies allow specific biological components to be examined in isolation under defined conditions.See also: In vivo, Preclinical
- In vivo
- In vivo is a Latin term meaning 'within the living' that describes experiments or processes studied inside a whole living organism rather than in an isolated preparation. In vivo research examines how a compound or process behaves within the complexity of a complete biological system.See also: In vitro, Preclinical
- Incretin
- A class of gut-derived hormones, including GLP-1 and GIP, released after nutrient intake that amplify glucose-stimulated insulin secretion. Incretins are a major focus of metabolic research on blood sugar regulation.See also: GLP-1, GIPRelated article →
- Insulin unit
- The insulin unit (U) is an international standard for expressing the quantity of insulin based on its biological activity rather than its mass. Insulin syringes are graduated in these units, and the scale is sometimes referenced when measuring very small liquid volumes in laboratory settings.See also: U-100, DilutionRelated article →
- Ipamorelin
- Ipamorelin is a synthetic pentapeptide that acts as a selective agonist of the ghrelin receptor, functioning as a growth hormone secretagogue. It is investigated in endocrine research for its selective stimulation of the growth hormone axis.See also: GHRP, CJC-1295Related article →
- Isomer
- An isomer is one of two or more molecules that share the same molecular formula but differ in the arrangement of their atoms. In peptide chemistry, isomers such as stereoisomers can display markedly different properties despite identical composition.
K
- Kd (dissociation constant)
- The dissociation constant (Kd) is an equilibrium constant that quantifies how tightly a ligand binds its receptor, equal to the ligand concentration at which half of the binding sites are occupied. A lower Kd indicates higher affinity, making it a key parameter for characterizing peptide-receptor interactions in biochemical research.See also: Ligand, Receptor, Agonist
- kDa (kilodalton)
- The kilodalton (kDa) is a unit of molecular mass equal to one thousand daltons, the dalton being an atomic mass unit that approximates the mass of a single hydrogen atom. In biochemical research, the masses of peptides and proteins are commonly expressed in daltons or kilodaltons to characterize and compare molecular size.See also: Molar mass, Molecular formula, Mass spectrometry
- Kinase
- A kinase is an enzyme that catalyzes the transfer of a phosphate group from ATP to a substrate molecule, a modification known as phosphorylation. In biochemical research, kinases are studied as central regulators of the intracellular signaling cascades engaged by many peptide receptors.See also: Receptor, Agonist
L
- Ligand
- Any molecule that binds specifically to a target protein such as a receptor, forming a complex that can influence the protein's activity. Ligands include hormones, neurotransmitters, peptides, and synthetic compounds studied for their binding properties.
- Lot number
- A lot number is a unique identifier assigned to a specific batch of material, allowing it to be traced back to its production run and associated quality records such as the certificate of analysis. It enables researchers to link a given container to the exact material that was manufactured and tested together.
- Lyophilisation
- Lyophilisation, or freeze-drying, is a dehydration process in which a frozen material is placed under vacuum so that its ice content sublimates directly from solid to vapour. It is commonly used to convert peptides into a stable dry powder, preserving structural integrity and extending shelf life for laboratory storage.See also: Reconstitution, VialRelated article →
M
- Mass spectrometry
- Mass spectrometry is an analytical technique that ionizes chemical compounds and sorts the resulting ions by their mass-to-charge ratio to determine molecular mass and structural information. In peptide research it is used to confirm a compound's identity and molecular weight, often complementing chromatographic purity analysis.See also: HPLC, Molar massRelated article →
- MC4R
- The melanocortin-4 receptor is a G protein-coupled receptor expressed primarily in the brain that is studied for its role in the regulation of energy balance, appetite, and body weight. It is a prominent target in metabolic and neuroendocrine research.See also: Melanocortin receptorRelated article →
- Melanocortin receptor
- A family of five G protein-coupled receptors (MC1R to MC5R) that bind melanocortin peptides and are involved in processes such as pigmentation, energy balance, and inflammation. They are studied across dermatological and metabolic research.See also: MC4R, AgonistRelated article →
- Melanotan II
- Melanotan II is a synthetic cyclic analog of the alpha-melanocyte-stimulating hormone (alpha-MSH). It acts as a non-selective agonist of melanocortin receptors and is studied in laboratory research on melanogenesis and pigmentation pathways.See also: Melanocortin receptor, MC4RRelated article →
- Molar mass
- Molar mass is the mass of one mole of a substance, usually expressed in grams per mole. For a peptide it is calculated by summing the masses of its constituent atoms and is used to prepare solutions and interpret analytical measurements.
- Molecular formula
- A molecular formula specifies the number and type of each atom present in a molecule, such as carbon, hydrogen, nitrogen, oxygen and sulfur. For peptides it summarizes the overall atomic composition but not the order of the residues.
- MOTS-c
- MOTS-c is a mitochondrial-derived peptide encoded within the mitochondrial genome. It is investigated in metabolic research for its proposed role in regulating cellular energy homeostasis, insulin sensitivity, and the response to metabolic stress.See also: SS-31, NAD+Related article →
N
- N-terminus
- The N-terminus is the end of a peptide or protein chain that carries a free amino group. By convention it is considered the start of the sequence and is written on the left when the sequence is notated.
- NAD+
- NAD+ (nicotinamide adenine dinucleotide) is a coenzyme present in all living cells that carries electrons in redox reactions. Central to cellular energy metabolism, it also serves as a substrate for enzymes involved in signaling and DNA repair, and is widely studied in aging and metabolism research.See also: MOTS-c, SS-31Related article →
O
- Oxidation
- Oxidation is a chemical reaction involving the loss of electrons from a molecule, often through interaction with oxygen or other oxidising agents. Certain amino acid residues, such as methionine and cysteine, are particularly susceptible to oxidation, which can alter a peptide's structure and is a common cause of degradation during storage.Related article →
P
- Pentadecapeptide
- A pentadecapeptide is a peptide made up of fifteen amino acid residues. The term describes chain length only; the specific sequence determines each pentadecapeptide's individual properties studied in the laboratory.
- Peptide
- A peptide is a short chain of amino acids linked by peptide bonds, typically containing fewer than about fifty residues. Peptides are studied in biochemical and pharmacological research for their diverse structural and signaling roles.See also: Amino acid, Protein, Peptide bond
- Peptide bond
- A peptide bond is the covalent amide linkage formed between the carboxyl group of one amino acid and the amino group of another, with the loss of a water molecule. It is the chemical connection that joins residues along a peptide or protein chain.
- Preclinical
- Preclinical refers to the stage of scientific investigation that takes place before any testing in humans, typically involving in vitro and in vivo laboratory research. Preclinical work is used to characterize a compound's properties and biological activity in experimental models.
- Protein
- A protein is a large biomolecule made of one or more long chains of amino acids that fold into specific three-dimensional structures. Proteins carry out most catalytic, structural and regulatory functions studied in cell and molecular biology.See also: Peptide, Amino acid
- Purity
- Purity is the proportion of a sample that consists of the target compound, expressed as a percentage of the total measured material, with the remainder comprising impurities such as related peptides, salts, or solvents. In peptide research it is commonly determined by HPLC, where the target peak's area is compared to the total peak area.See also: HPLC, Certificate of analysis (COA)Related article →
Q
- Quantification
- Quantification is the determination of the amount or concentration of a substance in a sample, such as measuring peptide content by high-performance liquid chromatography (HPLC) or ultraviolet absorbance. In peptide research it establishes net content and purity, supporting the characterization of laboratory preparations.See also: Purity, HPLC, Concentration
- Quaternary structure
- Quaternary structure is the highest level of protein organization, describing how multiple folded polypeptide subunits assemble and interact to form a single functional complex. In peptide and biochemical research, it is studied to understand how subunit composition and interfaces influence molecular stability, assembly, and activity in laboratory systems.See also: Protein, Sequence, Peptide bond
R
- Receptor
- A protein, typically located on the cell surface or inside the cell, that recognizes and binds a specific signaling molecule and converts that binding event into a cellular response. Receptors are central to how cells detect and respond to their chemical environment.See also: Ligand, Agonist
- Reconstitution
- Reconstitution is the process of returning a lyophilised (freeze-dried) solid to solution by adding a suitable liquid diluent. In peptide research it refers to dissolving a dry peptide powder in an appropriate solvent to obtain a solution of known concentration for laboratory analysis.See also: Bacteriostatic water, Lyophilisation, Concentration, DilutionRelated article →
- Research use only (RUO)
- Research use only (RUO) is a designation indicating that a product is intended solely for laboratory research and is not for use in diagnostic, therapeutic, or other clinical applications in humans or animals. Materials labeled RUO have not been evaluated or approved for medical use and are supplied only for controlled scientific investigation.Related article →
- Residue
- A residue is a single amino acid unit as it exists within a peptide or protein chain, after the loss of water during peptide bond formation. The number of residues is commonly used to describe the length of a peptide.
- Retatrutide
- Retatrutide is a synthetic peptide designed to act as a triple agonist at the GLP-1, GIP, and glucagon receptors. It is investigated in metabolic and endocrine laboratory research for its effects on energy balance and glucose regulation.See also: Tirzepatide, Semaglutide, GLP-1Related article →
S
- Semaglutide
- Semaglutide is a synthetic analog of the incretin hormone GLP-1 that binds and activates the GLP-1 receptor with prolonged stability. It is investigated in metabolic and endocrine research related to glucose regulation and appetite signaling.See also: GLP-1, TirzepatideRelated article →
- Sequence
- A sequence is the ordered arrangement of amino acid residues along a peptide or protein chain, conventionally written from the N-terminus to the C-terminus. This order determines the molecule's identity and its folding and functional properties.
- Spec sheet
- A spec sheet, or specification sheet, is a document that lists the defined properties and acceptance criteria for a material, such as its molecular formula, molecular weight, appearance, and required purity. It sets out the standards a product is expected to meet, against which test results on a batch can be compared.Related article →
- SS-31
- SS-31 is a synthetic mitochondria-targeting tetrapeptide, also referred to as elamipretide in research contexts. It is investigated for its selective binding to cardiolipin in the inner mitochondrial membrane and its studied effects on mitochondrial structure and bioenergetics.See also: Cardiolipin, MOTS-cRelated article →
- Sterile water
- Sterile water is purified water that has been processed to remove all viable microorganisms and contains no added preservatives. It is used as a diluent for reconstitution when a preservative-free solvent is required, though it does not inhibit microbial growth once the container is opened.See also: Bacteriostatic water
T
- TB-500
- TB-500 is a synthetic peptide corresponding to an active fragment of the protein thymosin beta-4. It is investigated in laboratory research for its role in actin regulation, cell migration, and tissue remodeling processes.Related article →
- Tesamorelin
- Tesamorelin is a synthetic analog of growth hormone-releasing hormone (GHRH). It is investigated in endocrine research for its interaction with GHRH receptors and its role in the regulation of the growth hormone axis.See also: GHRH, CJC-1295Related article →
- Third-party testing
- Third-party testing is the analysis of a product by an independent laboratory that has no commercial interest in the outcome, providing an unbiased verification of characteristics such as identity and purity. In research supply it is used to corroborate a manufacturer's own quality claims through an external check.
- Tirzepatide
- Tirzepatide is a synthetic peptide that acts as a dual agonist of the GIP and GLP-1 incretin receptors. It is studied in metabolic research for its influence on insulin signaling, glucose homeostasis, and energy metabolism.See also: Retatrutide, Semaglutide, GIPRelated article →
- Tripeptide
- A tripeptide is a peptide composed of three amino acid residues joined by two peptide bonds. Tripeptides are among the simplest peptides and are frequently used as models in structural and biochemical research.
U
- U-100
- U-100 denotes a standard insulin concentration of 100 units per millilitre and, by extension, the syringe scale calibrated to it. On a U-100 syringe, one millilitre is divided into 100 graduated units, a scale often referenced for measuring small liquid volumes in the laboratory.See also: Insulin unitRelated article →
V
- Vial
- A vial is a small glass or plastic container used to hold liquids or lyophilised powders, typically sealed with a rubber stopper and a metal crimp cap. In peptide research, vials store the dry or reconstituted compound and protect its contents from contamination and light.
W
- Water for injection (WFI)
- Water for injection (WFI) is highly purified, sterile, pyrogen-free water made to pharmacopeia standards as a solvent or diluent that, unlike bacteriostatic water, contains no preservative. In peptide and biochemical research it is used to reconstitute lyophilized compounds when a preservative-free, single-use vehicle is needed.See also: Bacteriostatic water, Sterile water, Reconstitution
- Western blot
- A Western blot is an analytical technique that separates proteins by gel electrophoresis, transfers them onto a membrane, and detects a specific target using antibodies. In peptide and biochemical research it is used to confirm the identity, presence, or relative abundance of a protein or peptide within a sample.See also: Mass spectrometry, HPLC, Third-party testing
X
- X-ray crystallography
- X-ray crystallography is a method that determines the three-dimensional atomic structure of a molecule by analyzing how a beam of X-rays diffracts as it passes through an ordered crystal of the sample. In peptide and biochemical research, it is used to resolve the precise conformation of peptides and their binding interactions at atomic resolution.See also: Protein, Sequence, Mass spectrometry
Y
- Yield
- Yield is the amount of a product actually obtained from a chemical reaction or synthesis, commonly expressed as a percentage of the theoretical maximum predicted by stoichiometry. In peptide research, it serves as a key measure of synthetic efficiency, informing the optimization of coupling, deprotection, and purification steps.See also: Batch, Purity, GMP
Z
- Zwitterion
- A zwitterion is a molecule that carries both a positive and a negative charge on distinct atoms yet remains electrically neutral overall. Amino acids and peptides exist predominantly in zwitterionic form at physiological pH, a property examined in biochemical research for its influence on solubility, folding, and separation behavior.See also: Amino acid, Peptide, Isomer