Research Index: Non-clinical summaries for educational and scientific discussion. Not medical advice.

Research Glossary

Definitions of common terminology used in peptide research, testing, and laboratory applications. This educational reference helps researchers understand scientific concepts and terminology.

A B C D H I L M P R S

A

Amino Acid: Organic molecules that serve as the building blocks of peptides and proteins. There are 20 standard amino acids used in biological systems, each with a specific side chain that determines its properties.

B

Bioavailability: The proportion of a compound that enters circulation and is available for biological activity. In research contexts, this affects experimental design and compound selection.

C

Certificate of Analysis (COA): A document from a testing laboratory reporting quality test results including purity, identity confirmation, molecular weight, and other specifications for a specific batch of compound.
Cyclization: A chemical modification where a peptide's ends are joined to form a ring structure, often improving stability and resistance to enzymatic degradation.

D

D-Amino Acid: Mirror-image (stereoisomer) form of standard L-amino acids. Incorporation of D-amino acids can increase peptide resistance to proteolytic degradation.

H

Half-Life: The time required for half of a compound to be degraded or eliminated. For peptides, this is influenced by enzymatic degradation and structural modifications.
HPLC (High-Performance Liquid Chromatography): An analytical technique that separates mixture components for identification and quantification. Used to determine peptide purity as a percentage of main compound.

I

In-Vitro: Latin for 'in glass.' Refers to experiments conducted outside a living organism, such as in test tubes, cell cultures, or other laboratory vessels.
In-Vivo: Latin for 'in the living.' Refers to experiments conducted within living organisms such as animals. In-vivo studies follow in-vitro research but precede human trials.

L

Lyophilization: Freeze-drying process that removes water from frozen compounds under vacuum. Produces stable powder form for long-term storage of peptides.

M

Mass Spectrometry (MS): Analytical technique measuring mass-to-charge ratio of molecules. Used to confirm peptide identity by comparing observed to theoretical molecular weight.
Molecular Weight: The sum of atomic weights of all atoms in a molecule, typically expressed in Daltons (Da) or g/mol. Used to verify peptide identity.

P

Peptide: Short chain of amino acids (typically 2-50) linked by peptide bonds. Smaller than proteins and often serve as signaling molecules or structural components.
Peptide Bond: Covalent chemical bond formed between the carboxyl group of one amino acid and the amino group of another through dehydration synthesis.
Preclinical: Research stage occurring before human clinical trials. Includes in-vitro studies and animal experiments to evaluate compound properties and safety.
Proteolysis: Enzymatic breakdown of proteins and peptides into smaller fragments. A primary mechanism of peptide degradation in biological systems.
Purity: The percentage of a sample consisting of the intended compound versus impurities. Typically measured by HPLC. High purity is ≥98% or ≥99%.

R

Receptor: A protein molecule that receives and responds to chemical signals. Many peptides exert effects by binding to specific cell surface or intracellular receptors.
Reconstitution: The process of dissolving a lyophilized (freeze-dried) compound in an appropriate solvent to create a solution for experimental use.

S

Secretagogue: A substance that promotes secretion. Growth hormone secretagogues, for example, stimulate the pituitary gland to release growth hormone.
Sequence: The specific order of amino acids in a peptide or protein. This sequence determines the compound's structure and biological properties.
Stability: A compound's resistance to degradation from environmental factors including temperature, pH, light, moisture, and enzymatic activity.
Sterile: Free from living microorganisms. Sterile technique and materials are essential for cell culture work and certain research applications.
Synthetic Peptide: A peptide produced through chemical synthesis (solid-phase or liquid-phase) rather than extracted from biological sources.

About This Glossary

This glossary provides simplified definitions for educational purposes. For comprehensive scientific understanding, researchers should consult primary literature, textbooks, and peer-reviewed sources. Terms are defined in the context of peptide research applications.