Peptide Glossary
The peptide and lab terms you will see on our product pages, explained in plain English with no chemistry degree needed. Supplied for laboratory research use only.
Welcome to the Pepcore glossary, a plain-English guide to the peptide and lab terms you will meet on our product pages and lab reports, from amino acids right through to what happens inside a cell.
Peptides are short chains of amino acids, the same building blocks that make up proteins, and they play a big part in how cells work. A lot of peptide research looks at how they switch a cell's receptors on or off: an "agonist" switches a receptor on, while an "antagonist" blocks it. This page explains all of that, plus the terms you will see on your lab reports, in everyday language. Everything Pepcore supplies is for laboratory research use only.
Peptide Basics
Start here. The simple ideas behind what a peptide actually is and what it is made of.
Amino Acid
The small building blocks that link together to make peptides and proteins. Picture beads on a string: a few beads make a peptide, lots of beads make a protein. There are twenty common ones.
Peptide
A short chain of amino acids joined together. Peptides are basically mini-proteins, and they are the core of everything Pepcore supplies for research.
Peptide Bond
The chemical "link" that joins one amino acid to the next, like the knot between two beads on a string. A tiny bit of water is released each time a link forms.
Residue
The name for a single amino acid once it is joined inside a chain. A peptide that is "ten residues long" simply has ten amino acids in it.
Sequence
The exact order of the amino acids in a peptide. The order is what makes each peptide unique, like how the order of letters makes a word.
Oligopeptide
A very short peptide, usually just a few amino acids (roughly two to twenty).
Polypeptide
A long chain of amino acids. Once a chain passes about fifty of them, it is usually called a protein instead.
Disulfide Bond
A tiny chemical "clip" that links two parts of a peptide together and helps it hold its shape.
Fragment
A small piece taken from a larger peptide or protein, used to study which part does the work.
Analog (Analogue)
A slightly tweaked version of a known peptide. Researchers change it a little to see how that small change affects the way it behaves.
Peptidomimetic
A man-made molecule built to copy what a natural peptide does, but made tougher or longer-lasting so it holds up better in research.
Synthetic Peptide
A peptide made in a lab from scratch, rather than taken from a plant or animal. Everything Pepcore supplies is synthetic.
Types of Peptides
The main families of peptides you will come across, and what makes each one different.
Bioactive Peptide
A peptide that is active when it meets living cells, which is why it gets studied. Examples include peptides looked at in germ-fighting and immune research.
Peptide Hormone
A peptide that works as a messenger in the body. Insulin and glucagon are two well-known natural examples you will see mentioned in the science.
Neuropeptide
A peptide that nerve cells use to send messages to each other. Studied a lot in brain and nervous-system research.
Bioregulator
A very short peptide (two to four amino acids) based on natural ones found in body tissue, studied for how it may affect cells.
GHRH / GHRP
Two groups of peptides studied in research on the body's growth-hormone system. The letters stand for growth hormone releasing hormone and growth hormone releasing peptides.
IGF (Insulin-like Growth Factor)
A natural protein the body uses for growth-related signals. Often referenced in cell research.
Somatostatin
A natural peptide studied for the way it helps switch certain other body signals on and off.
Mitochondrial Peptide
A peptide tied to the mitochondria, the tiny "power plants" inside cells, studied in research on cell energy.
Signal Peptide
A short "address label" at the start of a protein that tells the cell where to send it.
Cell Biology Basics
A quick tour of the cell, so the science on our product pages makes more sense.
Receptor
A "docking point" on or inside a cell. When the right molecule docks onto it, it sends a signal telling the cell to do something. Often pictured as a lock waiting for its key.
Ligand
Any molecule that fits into a specific spot on a protein, like a key into a lock, and changes what that protein does. The "key" for a receptor.
Agonist
A molecule that switches a receptor "on" and triggers a response in the cell.
Antagonist
A molecule that blocks a receptor so it cannot switch on. The opposite of an agonist.
Enzyme
A protein that speeds up a chemical reaction, like a helper that makes things happen faster. Enzymes run much of what goes on inside cells.
Cytokine
A small protein that cells use to talk to each other, especially the immune system.
Cell Membrane
The thin "skin" around a cell that decides what gets in and what stays out.
Nucleus
The cell's control centre. A sealed compartment that holds the DNA, the instruction manual for the whole cell.
Mitochondria
The "power plants" of the cell. They turn food and oxygen into the energy the cell runs on.
Ribosome
The cell's "assembly line." It reads the genetic instructions and builds proteins from them.
Endoplasmic Reticulum (ER)
A folded "factory floor" inside the cell where proteins and fats are put together.
Golgi Apparatus
The cell's "packaging and shipping department." It finishes off proteins and sends them where they need to go.
Purity & Lab Testing
What the numbers and tests on your Certificate of Analysis actually mean.
Purity
How much of what is in the vial is the real target peptide. It is measured by HPLC, and Pepcore peptides test at 99% or higher.
HPLC (High-Performance Liquid Chromatography)
The lab test used to check how pure a peptide is. A 99% result means the vial is at least 99% the target peptide, with under 1% of anything else. It is the main number on your COA.
Certificate of Analysis (COA)
The lab report that comes with every Pepcore product. It confirms what the product is, its batch number, and how pure it tested.
Mass Spectrometry (MS)
A lab test that weighs a molecule very precisely to confirm it really is the peptide it should be. Usually shown next to the HPLC result on a COA.
Molecular Weight (MW)
How much one molecule of a peptide weighs. It helps confirm the compound and work out amounts.
CAS Number
A unique ID code given to each chemical, so there is never any confusion about which exact compound you mean.
In Vitro
Latin for "in glass." It means research done in test tubes or dishes, outside a living body. Everything Pepcore sells is for in-vitro research only.
Half-life
How long it takes for half of a compound to break down. A longer half-life means it lasts longer before it fades.
Net Peptide Content
The share of the powder in the vial that is actually peptide, once the small bits that come attached during manufacturing are accounted for.
Isoelectric Point (pI)
The exact acidity level at which a peptide carries no overall charge. A technical detail that affects how easily it dissolves.
Molar Ratio
In a blend, the exact proportion of one peptide to another, kept the same every time so results stay consistent.
Reference Compound
A well-known, well-studied peptide used as a yardstick to compare others against.
Solid-Phase Peptide Synthesis (SPPS)
The standard way peptides are made: building the chain one amino acid at a time on a tiny support.
Storage & Handling
Plain-English terms for storing peptides and getting them ready in the lab.
Lyophilized Powder
The freeze-dried powder form that all Pepcore peptides arrive in.
Lyophilization (Freeze-drying)
Drying a peptide by freezing it and pulling out the water, leaving a stable powder that travels and stores well.
Reconstitution
Adding liquid to the freeze-dried powder to turn it back into a solution for lab work.
Diluent
The liquid used to dissolve a freeze-dried peptide so it can be worked with.
Solubility
How easily a peptide dissolves in a given liquid. Some need a particular liquid to dissolve fully.
Working Stock
A ready-to-use, diluted solution made from a stronger one, kept handy for everyday lab use.
Blend
One vial holding two or more peptides mixed at a set ratio, so they can be studied together instead of separately.
Counter-ion
A small "partner" molecule (often acetate) attached to a peptide to keep it stable as a powder. Just part of how peptides are supplied.
Acetate Salt
A small partner molecule (acetate) attached to many peptides to help keep the dry powder stable.
TFA Salt (Trifluoroacetic Acid)
Another partner molecule that some peptides come with, similar in job to acetate.
Excipient
An extra ingredient sometimes added to a vial to help protect or bulk out the peptide.
Cysteine
One of the amino acids. Its special trick is forming the little "clips" (disulfide bonds) that hold a peptide's shape.
Tagged / Untagged
Whether a peptide has an extra marker attached to it (tagged) or is the plain version with nothing added (untagged).
Research Use Only (RUO)
A label meaning the product is strictly for laboratory research, not for use in people or animals.
Frequently Asked Questions
Quick answers to the questions we hear most.
What is a peptide?
A peptide is a short chain of amino acids, the same building blocks that make up proteins. In research, peptides are studied as compounds in cell, biochemical, and analytical models.
What does HPLC purity mean?
HPLC is the lab test that measures how pure a peptide is. A 99% result means at least 99% of the vial is the target peptide. Pepcore peptides test at 99% or higher, and the result is shown on the Certificate of Analysis.
What is a COA?
A Certificate of Analysis is the lab report that comes with every product. It identifies the batch and shows the test results, such as HPLC purity and a mass check that confirms the peptide's identity.
Are Pepcore peptides for human use?
No. Everything Pepcore supplies is strictly for laboratory research use only, and is not for use in people or animals.
Every Pepcore peptide arrives as a 99%+ pure freeze-dried powder with a Certificate of Analysis. All products are for laboratory research use only, and are not for use in people or animals.