01 · FOUNDATIONS
Core Peptide Science
Agonist
A substance that binds to a receptor and activates it, producing a measurable biological response within an experimental system.
Amino Acids
Organic compounds that join together to form peptides and proteins. Each amino acid contains an amino group, a carboxyl group and a variable side chain that influences its chemical properties.
Antagonist
A substance that binds to a receptor without activating it and can reduce or block the action of an agonist.
Bioactive Peptides
Peptide sequences capable of interacting with biological systems. In research, they may be investigated for their involvement in processes such as cell signalling, immune activity or antimicrobial responses.
Enzyme
A biological catalyst that speeds up a chemical reaction without being permanently consumed by it. Many enzymes are proteins, although some RNA molecules can also act as catalysts.
GHRP (Growth Hormone-Releasing Peptide)
A class of synthetic peptides studied for their interaction with receptors and signalling pathways associated with growth hormone release.
Mitochondrial Peptides
Peptides encoded by mitochondrial DNA, or peptides studied for their influence on mitochondrial processes such as energy regulation, cellular stress responses and programmed cell death.
Neuropeptide
A small peptide used by neurons and other cells for communication. Neuropeptides are widely studied for their roles in nervous-system signalling and the regulation of physiological processes.
Oligopeptide
A relatively short chain of amino acids. The term is commonly used for peptides containing approximately two to twenty amino-acid residues.
Peptide
A molecule formed when two or more amino acids are connected by peptide bonds. Peptides vary greatly in length, structure and biological activity.
Peptide Bond
The covalent link formed between the carboxyl group of one amino acid and the amino group of another. Formation of this bond releases a molecule of water.
Peptide Hormone
A peptide that acts as a chemical messenger in a biological system. Examples include insulin and glucagon, both of which take part in metabolic signalling.
Peptidomimetic
A molecule designed to reproduce selected structural or functional features of a peptide. Peptidomimetics may be investigated for improved stability, selectivity or resistance to enzymatic breakdown.
Polypeptide
A continuous chain containing many amino acids. There is no single universal cut-off, but longer, folded polypeptide chains are generally described as proteins.
Protein
A biological macromolecule made from one or more folded polypeptide chains. Proteins perform structural, catalytic, transport and signalling functions in living systems.
Signal Peptide
A short amino-acid sequence, usually found at the beginning of a newly produced protein, that helps direct the protein to a particular cellular location or secretion pathway.
Somatostatin
A naturally occurring peptide hormone involved in inhibitory endocrine signalling. It is studied for its role in regulating the release of several other hormones.
Synthetic Peptide
A peptide produced using controlled chemical or biological manufacturing methods. Synthetic peptides allow researchers to study defined sequences, modifications and molecular interactions.
02 · MOLECULAR INTERACTIONS
Receptors and Molecular Signalling
Binding Affinity
A measure of how strongly a molecule, such as a ligand, interacts with its binding site. Higher affinity generally indicates a stronger molecular interaction under the conditions tested.
Cytokine
A small signalling protein released by cells. Cytokines help coordinate communication between cells and are frequently studied in immune and inflammatory research.
Ligand
A molecule that binds to a specific site on another molecule, commonly a receptor or enzyme. Binding may activate, inhibit or otherwise alter the function of the target.
Receptor
A protein located on a cell surface or inside a cell that recognises particular ligands. Ligand binding can initiate or modify a cellular response.
Selectivity
The extent to which a molecule interacts with one target more readily than with other possible targets.
Signalling Pathway
A sequence of molecular events through which a cell receives, processes and responds to a signal.
03 · INSIDE THE CELL
Cellular and Molecular Biology
Cell Membrane
The selectively permeable boundary surrounding a cell. It separates the cell from its environment and helps control transport, communication and cellular homeostasis.
Endoplasmic Reticulum (ER)
An interconnected membrane system within eukaryotic cells. Rough ER is associated with protein production and processing, while smooth ER contributes to lipid synthesis and other cellular functions.
Golgi Apparatus
A cellular organelle that modifies, sorts and packages proteins and lipids before directing them to their appropriate destination.
Mitochondria
Organelles best known for producing cellular energy in the form of ATP. They are also involved in metabolism, calcium regulation, cell signalling and programmed cell death.
Nucleus
The membrane-bound compartment in most eukaryotic cells that contains the majority of the cell's genetic material.
Ribosome
A molecular complex that reads messenger RNA and assembles amino acids into a polypeptide chain during protein synthesis.
04 · LABORATORY LANGUAGE
Common Laboratory Terms
Certificate of Analysis (CoA)
A document reporting specified test results for a particular product or batch. Depending on the testing performed, it may include information such as identity, purity or other analytical data.
Half-Life
The time required for the amount or concentration of a substance to fall to half of its starting value under defined conditions.
In Vitro
Research carried out outside a living organism, typically in controlled laboratory equipment such as test tubes, culture plates or similar systems.
Lyophilised
Freeze-dried. Lyophilisation removes water from a frozen material under reduced pressure and is commonly used to improve stability during storage.
Read the full guide: What does lyophilised mean?Purity
The proportion of the intended substance within a sample relative to detectable impurities, as measured by a stated analytical method.
Reconstitution
The process of adding a suitable liquid to a dried or lyophilised material so it returns to solution for an authorised laboratory procedure.
Stability
The ability of a substance to retain its identity, composition and relevant properties over time when kept under specified conditions.
QUICK ANSWERS
Peptide Glossary FAQs
What is the difference between a peptide and a protein?
Both are made from amino acids. Peptides are generally shorter chains, while proteins are usually longer and fold into more complex three-dimensional structures. The boundary between the two terms is not absolute.
What holds amino acids together in a peptide?
Amino acids in a peptide chain are joined by covalent peptide bonds.
Why are receptors important in peptide research?
Many peptides exert an effect in an experimental system by binding to a particular receptor. Studying that interaction can help researchers understand signalling, selectivity and downstream cellular responses.
What does “for research purposes only” mean?
It means the material is supplied solely for legitimate laboratory and analytical research. It is not a medicine and is not intended for human or veterinary use, consumption, diagnosis, treatment or any clinical application.
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