Reference

Peptide Glossary

A comprehensive reference guide to common peptide research terminology, techniques, and concepts.

A

Amino Acid
The building blocks of peptides and proteins. There are 20 standard amino acids, each with a unique side chain that determines its chemical properties.
Analogue
A synthetic peptide with a modified structure compared to the naturally occurring version, often designed to improve stability, potency, or selectivity.
Amidation
A post-translational modification where the C-terminal carboxyl group is converted to an amide group, often increasing peptide stability and biological activity.

B

Bacteriostatic Water
Sterile water containing 0.9% benzyl alcohol as a preservative. Used for reconstituting lyophilised peptides, it prevents bacterial growth and allows multi-use from a single vial.
Bioavailability
The proportion of a substance that enters circulation when introduced into the body and is able to have an active effect. Route of administration significantly affects bioavailability.
BPC-157
Body Protection Compound-157. A synthetic peptide derived from a protein found in gastric juice. Consists of 15 amino acids. Widely studied for tissue repair properties.

C

Certificate of Analysis (CoA)
A document issued by a quality control laboratory that confirms a product meets its specified quality standards. For peptides, typically includes HPLC purity data, mass spectrometry identity confirmation, and appearance.
CAS Number
Chemical Abstracts Service registry number. A unique numerical identifier assigned to every chemical substance described in the open scientific literature.
Cyclic Peptide
A peptide chain that forms a ring structure through a bond between the N-terminus and C-terminus, or between two side chains. Often more stable than linear peptides.

D

Dalton (Da)
A unit of mass used to express the molecular weight of molecules. 1 Dalton equals approximately 1.66 × 10⁻²⁴ grams. Peptide weights are typically expressed in Daltons.
Disulphide Bond
A covalent bond formed between two cysteine residues. Important for maintaining the three-dimensional structure of peptides and proteins.

G

GH Secretagogue
A substance that stimulates the secretion of growth hormone from the pituitary gland. Includes both peptide (e.g., GHRP-6, Ipamorelin) and non-peptide compounds.
GLP-1
Glucagon-like peptide-1. An incretin hormone produced in the gut that stimulates insulin secretion, inhibits glucagon release, and promotes satiety.

H

HPLC
High-Performance Liquid Chromatography. An analytical technique used to separate, identify, and quantify components in a mixture. The primary method for determining peptide purity.
Half-life
The time required for the concentration of a substance to decrease by half. Peptide half-lives can range from minutes to hours depending on structure and modifications.

L

Lyophilisation
Freeze-drying. A process used to preserve peptides by removing water through sublimation under vacuum. Lyophilised peptides are more stable and have longer shelf lives than solutions.
Ligand
A molecule that binds to a specific receptor to produce a biological response. Peptides can act as ligands for various cellular receptors.

M

Mass Spectrometry (MS)
An analytical technique that measures the mass-to-charge ratio of ions. Used to confirm the identity of peptides by determining their exact molecular weight.
Molecular Weight
The sum of the atomic weights of all atoms in a molecule, expressed in Daltons (Da). Used to confirm peptide identity via mass spectrometry.

P

Peptide
A short chain of amino acids linked by peptide bonds. Generally defined as 2-50 amino acids in length. Larger chains are typically called proteins.
Peptide Bond
A covalent chemical bond formed between two amino acids when the carboxyl group of one reacts with the amino group of another, releasing a water molecule.
Purity
The percentage of the desired peptide in a sample, as determined by HPLC analysis. Research-grade peptides typically have ≥95% purity; high-purity grades ≥98%.

R

Reconstitution
The process of dissolving a lyophilised (freeze-dried) peptide in a suitable solvent, such as bacteriostatic water, to prepare it for use.
Reverse Phase HPLC
The most common HPLC method for peptide analysis. Uses a non-polar stationary phase and a polar mobile phase to separate peptides based on their hydrophobicity.

S

Solid Phase Peptide Synthesis (SPPS)
The standard method for synthesising peptides, where amino acids are sequentially attached to an insoluble resin support. Allows automated, high-purity synthesis.
Sequence
The specific order of amino acids in a peptide chain, typically written from N-terminus (left) to C-terminus (right) using three-letter or single-letter amino acid codes.

T

TFA Salt
Trifluoroacetic acid salt. A counter-ion commonly present in synthetic peptides after HPLC purification. May be exchanged for acetate salt when TFA-free products are required.
TB-500
Thymosin Beta-4 fragment. A synthetic peptide representing the active region of the naturally occurring protein Thymosin Beta-4. Studied for tissue repair and wound healing.