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Peptide Molecular Icons
150 icons built from real amino acid sequences. Each one encodes residue count, chemical class, and relative mass into a visual fingerprint you can use in slides, articles, apps, and research.
How Peptide Icons Encode Sequence Data
Bubble = Residue
Each circle stands for one residue in a peptide's primary sequence. A 15-residue peptide like BPC-157 has 15 bubbles. A tripeptide like KPV has 3.
Size = Relative Residue Mass
Bubble area is proportional to residue mass. Tryptophan (heaviest) gets the largest bubble. Glycine (lightest) gets the smallest. Heavier residues pack toward the center.
Color = Chemical Class
Five residue classes, five colors: hydrophobic, polar, positive, negative, and special. Category palettes change the look, but the class mapping stays consistent.
Browse & Download Peptide Icons
Flat no haloStandard soft glowGlow stronger haloFree for noncommercial use with credit. License detailsWhat Peptide Icons Show and Don't Show
Every icon balances visual clarity with scientific accuracy. Here's what each one encodes — and the limits of what a 2D icon can show.
Residue count, chemical class, relative mass, and backbone connectivity. Cyclic peptides show a closed ring.
D-amino acids and L-amino acids look the same. Simplified icons use the closest standard residue.
Fatty acid chains (semaglutide), PEGylation, acetylation, and amidation are not shown.
No folding, surface geometry, or binding sites. These are flat 2D maps, not molecular models.
No claims about efficacy, safety, or what the peptide does in the body.
About compound icons: 21 entries (MK-677, NAD+, L-Carnitine, etc.) are small molecules with no amino acid chain. Their icons use a different visual pattern — you can tell them apart at a glance.
Amino Acid Classification
The visual system groups standard amino acids into five biochemical classes. That keeps the palette readable while still tying color to chemistry.
| Class | Amino Acids | Properties |
|---|---|---|
| Hydrophobic | Ala (A), Ile (I), Leu (L), Met (M), Phe (F), Trp (W), Val (V), Pro (P) | Nonpolar side chains — tend to cluster in the protein interior |
| Polar | Ser (S), Thr (T), Asn (N), Gln (Q), Tyr (Y) | Uncharged but polar — form hydrogen bonds with water |
| Positive Charge | Arg (R), Lys (K), His (H) | Positively charged at physiological pH — often on protein surfaces |
| Negative Charge | Asp (D), Glu (E) | Negatively charged at physiological pH — involved in salt bridges |
| Special | Gly (G), Cys (C) | Glycine enables tight turns; Cysteine forms disulfide bonds |
Use, Credit, and Commercial Licensing
You can use these icons free for personal, editorial, educational, and other noncommercial work if you credit Peptide Schedule. If you want to use them in a product, app, client deliverable, ad, paid course, or other business setting, you need a commercial license.
Peptide Tools
Frequently Asked Questions
What do the peptide icons represent?
Each icon is a visual fingerprint of a peptide's amino acid sequence. Every bubble is one residue. Bigger bubbles mean heavier residues. Colors map to five chemical classes: hydrophobic, polar, positive, negative, and special.
Are all 150 icons based on real sequences?
129 are. 102 icons use verified sequences from published research. 27 more use simplified sequences where non-standard residues (like D-amino acids) are swapped for the closest standard match. The other 21 entries are non-peptide compounds like MK-677 and NAD+ — they don't have amino acid sequences, so they get a different visual style.
What does “simplified” mean?
Some peptides use modified amino acids that don't have a standard single-letter code. For example, Melanotan II contains norleucine. In those cases, we use the closest standard amino acid so the icon still reflects the real structure — just not with 100% chemical precision.
What about the 21 compound icons?
Entries like MK-677, NAD+, testosterone, and L-Carnitine aren't peptides. They're small molecules with no amino acid chain. Their icons use a different visual pattern so you can tell them apart at a glance. Same design system, different encoding.
Are these 3D molecular models?
No. These are flat, 2D visual maps. They show residue count, residue type, and relative mass — not 3D folding, receptor binding, or biological activity.
Can I use these icons in my project?
Yes. Personal, educational, and noncommercial use is free with credit to Peptide Schedule. Commercial use (apps, products, ads, client work) needs a separate license.
What should the credit line look like?
”Icons by Peptide Schedule” with a link to peptideschedule.com/tools/peptide-icons. Put it wherever people can find it — caption, footer, credits page, or about screen.