Comprehensive Peptide Glossary

Key terms in peptide science — from amino acids and receptors to cellular biology and laboratory methodology. 35 terms.

Introduction to Peptide Science

Peptides — chains of amino acids linked by peptide bonds — are a fundamental category of biological molecules with pivotal roles in cellular processes and scientific research. Understanding the dichotomy between agonists and antagonists, and how they interact with cellular receptors, is essential for comprehending the mechanistic basis of peptide function in biological systems.

Key Terms in Peptide Science

Amino Acids: The building blocks of proteins and peptides, consisting of a central carbon atom, an amino group, a carboxyl group, and a distinctive side chain.
Bioactive Peptides: Peptides studied for their interactions with biological systems in laboratory research, including antimicrobial and immunological signalling studies.
Enzymes: Proteins that catalyse biochemical reactions in living organisms, often playing critical roles in metabolism and signalling pathways.
GHRP (Growth Hormone-Releasing Peptides): Synthetic peptides studied for their interaction with growth hormone (GH) signalling pathways.
Mitochondrial Peptides: Peptides that are encoded by mitochondrial DNA or influence mitochondrial function, involved in energy production and apoptosis.
Neuropeptides: Small protein-like molecules used by neurons to communicate with each other, involved in many physiological signalling pathways studied in neuroscience research.
Oligopeptide: A peptide consisting of a few amino acids, typically between two and twenty.
Peptide Bond: A covalent chemical bond formed between two amino acid molecules when the carboxyl group of one molecule reacts with the amino group of the other, releasing a molecule of water (H₂O).
Peptide Hormones: Chains of amino acids that function as hormones in the body, such as insulin and glucagon, involved in metabolic signalling pathways.
Peptidomimetics: Small protein-like chains designed to mimic the biological activity of a natural peptide but with enhanced stability, bioavailability, or specificity.
Polypeptide: A long, continuous chain of amino acids. Polypeptides with more than 50 amino acids are typically considered proteins.
Receptor: Proteins on the cell surface or within cells that recognise and bind specific molecules (ligands), triggering a biological response.
Somatostatin: A peptide hormone that inhibits the release of several other hormones, including growth hormone and insulin, playing a critical role in the endocrine system.
Signal Peptide: A short peptide present at the N-terminus of a protein that directs the protein to specific destinations within or outside the cell.
Synthetic Peptides: Peptides that are artificially made using peptide synthesis techniques, often designed to mimic or modify the function of natural peptides for research purposes.

Cellular and Molecular Terms

Cell Membrane: The semipermeable membrane surrounding the cytoplasm of a cell, which regulates the passage of substances in and out of the cell.
Cytokines: Small proteins released by cells that have a specific effect on the interactions and communications between cells, often involved in immune responses.
Endoplasmic Reticulum (ER): A network of membranous tubules within the cytoplasm of a cell, involved in protein and lipid synthesis.
Golgi Apparatus: An organelle in cells that modifies, sorts, and packages proteins for secretion or delivery to other organelles.
Ligand: A molecule that binds to a specific site on a protein, such as a receptor, influencing the function of the protein.
Mitochondria: Organelles found in large numbers in most cells, involved in the production of energy through aerobic respiration.
Nucleus: A membrane-bound organelle within eukaryotic cells that contains the genetic material (DNA).
Ribosome: A complex molecular machine found within all living cells that performs the synthesis of proteins according to the sequence of messenger RNA (mRNA).

Pharmacology & Receptor Interaction

Agonist: A molecule that binds to a receptor and activates it to produce a biological response, mimicking the action of an endogenous ligand.
Antagonist: A molecule that binds to a receptor without activating it, blocking the action of agonists or endogenous ligands.
Half-Life: The time required for the concentration of a substance in the body to reduce by half, an important measure in pharmacokinetics.
Bioavailability: The proportion of an administered substance that reaches the systemic circulation in active form.
Pharmacokinetics: The study of how a substance is absorbed, distributed, metabolised and excreted by the body.

Research Methodology

Lyophilisation: Freeze-drying process used to preserve peptides in a stable, dry form for long-term storage and shipping.
Reconstitution: The process of dissolving a lyophilised peptide in a suitable solvent (typically bacteriostatic water) for laboratory use.
Bacteriostatic Water: Sterile water containing 0.9% benzyl alcohol used to reconstitute peptides; the alcohol inhibits bacterial growth.
HPLC (High-Performance Liquid Chromatography): An analytical technique used to separate, identify and quantify components in a mixture, commonly used to verify peptide purity.
Mass Spectrometry: An analytical technique that measures the mass-to-charge ratio of ions, used to confirm peptide molecular weight and identity.
COA (Certificate of Analysis): A document issued by a manufacturer detailing test results for a specific batch of product, including purity and identity.
In Vitro: Latin for 'in glass' — research performed outside a living organism, typically in a controlled laboratory environment.

For in vitro research only. Not for human or veterinary use.