Random Amino Acid Generator

One press gives an amino acid; say its codes, then tap to check.

Random Amino Acid Generator

  1. Isoleucine
All 22

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How it works

This random amino acid generator draws one of the 20 amino acids of the standard genetic code, or one of two rarer ones. Say its three-letter and one-letter codes, then tap to see both.

Read the full guide

Drill the codes

Press the button, say the codes out loud, then tap the cover: Tryptophan is Trp and W, Glutamine is Gln and Q, Lysine is Lys and K. Set the count to 5 for a quick test. After your first press, the chips keep the draw to The standard 20, or to the acidic and basic or the aromatic side chains.

Why some one-letter codes look odd

Of the standard 20, eleven one-letter codes are the amino acid's first letter and nine are not. Alanine has A, so arginine is R, asparagine N and aspartic acid D. Phenylalanine is F, tyrosine Y and tryptophan W. Those nine are the ones worth drilling.

Tips
  • Learn the three-letter codes first. Most are the first three letters; asparagine (Asn), glutamine (Gln), isoleucine (Ile) and tryptophan (Trp) are not.
  • The two extras, selenocysteine (Sec, U) and pyrrolysine (Pyl, O), have a chip of their own.

Questions and answers

How many amino acids are there?

Living things use 22 to build proteins. Twenty are in the standard genetic code, and selenocysteine and pyrrolysine are added by special mechanisms. The standard 20 have a chip of their own.

Which amino acids are acidic and which are basic?

Aspartic acid and glutamic acid have acidic side chains. Lysine, arginine and histidine have basic ones. Pick the Acidic or basic side chain chip to draw only those five.

What are the aromatic amino acids?

The table this list was read from marks four side chains as aromatic: phenylalanine, tyrosine, tryptophan and histidine.

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All 22 amino acids

The standard 20 20

  • Alanine Ala, one-letter code A.
  • Arginine Arg, one-letter code R. A basic side chain.
  • Asparagine Asn, one-letter code N.
  • Aspartic acid Asp, one-letter code D. An acidic side chain.
  • Cysteine Cys, one-letter code C.
  • Glutamic acid Glu, one-letter code E. An acidic side chain.
  • Glutamine Gln, one-letter code Q.
  • Glycine Gly, one-letter code G.
  • Histidine His, one-letter code H. A basic side chain. It is aromatic too.
  • Isoleucine Ile, one-letter code I.
  • Leucine Leu, one-letter code L.
  • Lysine Lys, one-letter code K. A basic side chain.
  • Methionine Met, one-letter code M.
  • Phenylalanine Phe, one-letter code F. An aromatic side chain.
  • Proline Pro, one-letter code P.
  • Serine Ser, one-letter code S.
  • Threonine Thr, one-letter code T.
  • Tryptophan Trp, one-letter code W. An aromatic side chain.
  • Tyrosine Tyr, one-letter code Y. An aromatic side chain.
  • Valine Val, one-letter code V.

The two extras 2

  • Pyrrolysine Pyl, one-letter code O. One of the two outside the standard 20.
  • Selenocysteine Sec, one-letter code U. One of the two outside the standard 20.
How this list was compiled

A closed set: the 22 proteinogenic amino acids, which are the 20 of the standard genetic code and two more, selenocysteine and pyrrolysine. Names, three-letter and one-letter codes, and the acidic, basic and aromatic side chains were read by script on 2026-09-30 from the side-chain properties table of https://en.wikipedia.org/wiki/Proteinogenic_amino_acid, whose opening gives the counts of 22 and 20. Acidic is kept to aspartic acid and glutamic acid, and basic to lysine, arginine and histidine, where the table agrees with the usual textbook grouping; hydrophobic and polar are left off the cards because textbooks draw that line in different places. Wording is our own. Licence: own work