Glossary
Peptide science terminology.
Plain-language definitions for receptors, signalling molecules, peptide families and laboratory terms. Each entry links to the research peptides it relates to.
Agonist
A molecule that binds a receptor and activates it to produce a biological response.
Alcohol swab
Single-use isopropyl-alcohol (70%) prep pad used to disinfect vial septa and injection sites before puncture, maintaining sterile-field integrity during reconstitution and aliquoting.
Allosteric modulator
A ligand that binds a receptor site distinct from the orthosteric (primary) site, altering receptor response without directly activating it.
AMPK
AMP-activated protein kinase — a cellular energy sensor activated by low ATP:AMP ratio. Target of metformin and MOTS-c.
Amino acid
Organic molecule containing an amine and carboxyl group; the monomer of peptides and proteins. 20 standard residues in human biology.
Bacteriostatic water
Sterile water containing 0.9% benzyl alcohol as a preservative; the standard diluent for reconstituting lyophilised peptides in research settings. The benzyl alcohol inhibits bacterial growth, allowing multi-use of a reconstituted vial for up to ~28 days when refrigerated.
Borosilicate vial
Type-I borosilicate glass vial engineered for pharmaceutical and laboratory storage — chemically inert, low thermal expansion and resistant to leachables. The reference-standard container for lyophilised peptides.
Insulin syringe
Low-dead-space U-100 syringe (typically 0.3–1 mL) with a fixed 29–31 G needle. Used in peptide research for precise micro-volume aliquoting from a reconstituted vial.
Reconstitution
The laboratory process of dissolving a lyophilised (freeze-dried) peptide in an appropriate diluent — typically bacteriostatic water — to prepare a solution of known concentration for research use.
BDNF
Brain-derived neurotrophic factor — a neurotrophin that supports neuronal survival, plasticity and LTP. Upregulated by Semax and exercise.
Bioavailability
The fraction of an administered dose that reaches systemic circulation. Peptides typically have low oral bioavailability due to GI proteolysis.
BPC-157
Body Protection Compound 157 — a 15-amino-acid pentadecapeptide derived from gastric juice, studied for tissue-repair and cytoprotective effects.
Cardiolipin
A unique phospholipid found exclusively in the inner mitochondrial membrane; binding target of SS-31 (elamipretide).
cAMP
Cyclic adenosine monophosphate — second messenger produced by adenylyl cyclase following Gαs-coupled GPCR activation.
CJC-1295
A GHRH analogue with substitutions improving half-life. The DAC variant binds albumin covalently for ~8-day half-life.
COA (Certificate of Analysis)
A document from a manufacturer detailing purity, identity, and quality testing for a specific lot of a chemical product.
Epitope
The portion of an antigen that is recognised by an antibody or T-cell receptor.
GHRH
Growth-hormone-releasing hormone — a 44-aa hypothalamic peptide that stimulates pituitary GH secretion via the GHRH receptor.
GHRP
Growth-hormone-releasing peptide — synthetic peptides (e.g. GHRP-2, GHRP-6, ipamorelin, hexarelin) that activate the ghrelin/GHS-R1a receptor.
GLP-1
Glucagon-like peptide-1 — an incretin hormone from intestinal L-cells that potentiates glucose-dependent insulin secretion and slows gastric emptying.
GPCR
G-protein coupled receptor — a seven-transmembrane receptor family that transduces extracellular signals via heterotrimeric G-proteins. ~34% of FDA-approved drugs target GPCRs.
Half-life (t½)
The time required for the plasma concentration of a substance to decrease by half.
HPLC
High-performance liquid chromatography — the standard analytical method for assessing peptide purity (typically reverse-phase C18).
IGF-1
Insulin-like growth factor 1 — hepatically produced in response to GH; mediates many anabolic actions of growth hormone.
Incretin
Class of metabolic hormones (GLP-1, GIP) released after eating that stimulate insulin secretion.
Lyophilisation
Freeze-drying — process used to preserve peptides as stable, water-free powders for long-term storage.
MC4R
Melanocortin-4 receptor — GPCR in the hypothalamic PVN involved in appetite, energy balance and sexual-arousal pathways.
MOTS-c
A 16-amino-acid mitochondrial-derived peptide encoded within the mtDNA 12S rRNA gene; activates AMPK and improves insulin sensitivity.
Pharmacokinetics (PK)
Study of what the body does to a drug — absorption, distribution, metabolism and excretion.
Pharmacodynamics (PD)
Study of what a drug does to the body — receptor binding, signalling and biological response.
Pulsatile secretion
Hormonal release in discrete bursts rather than continuously; characteristic of physiological GH, GnRH and ACTH.
Receptor agonism
Activation of a receptor by a ligand to produce a downstream biological effect.
Receptor antagonism
Blockade of receptor activity by a ligand that binds without activating it.
Selectivity
The relative affinity of a ligand for one receptor or subtype over others.
SPPS
Solid-phase peptide synthesis — Merrifield's method (1963) for stepwise peptide chain assembly on an insoluble resin.
SS-31 (elamipretide)
A tetrapeptide that binds cardiolipin on the inner mitochondrial membrane, stabilising electron-transport-chain function.
TB-500
A synthetic 7-aa fragment (LKKTETQ) of thymosin β-4, studied for endothelial migration and tissue repair.
Thymosin α-1
A 28-aa immunomodulatory peptide that promotes T-cell maturation via TLR9 signalling. Licensed in many countries for hepatitis B.
VEGFR
Vascular endothelial growth factor receptor — tyrosine kinase receptor driving angiogenesis; upregulated by BPC-157 in preclinical models.