U. C. Davis, Biological Sciences

Amino Acid Properties

This list is provided as a study guide to help remind you of the properties of the side chains/R-groups of the twenty amino acids which are present in newly synthesized proteins. The R-groups can be classified in many different ways, several of which are described below. You should not need to memorize the list, but should be able to predict the properties from your knowledge of the structures of the side chains and basic principles of organic chemistry. To learn more about an amino acid, to find out which amino acid a one letter code abbreviates, and to veiw its structure click on it!

  1. All - G, A, V, L, I, P, F, Y, W, S, T, N, Q, C, M, D, E, H, K, R
  2. Polar / hydrophilic - N, Q, S, T, K, R, H, D, E, (C, Y)*
  3. Non-polar / hydrophobic - (G), A, V, L, I, P, Y, F, W, M, C
  4. H-bonding - C, W, N, Q, S, T, Y, K, R, H, D, E
  5. Sulfur containing - C, M
  6. Charged at Neutral pH Negative / acidic - D, E, (C)
  7. Charged at Neutral pH Positive / basic - K, R, (H)
  8. Ionizable - D, E, H, C, Y, K, R
  9. Aromatic - F, W, Y, (H, but no significant UV absorption)
  10. Aliphatic - G , A, V, L, I, P
  11. Forms covalent cross-link (disulfide bond) - C
  12. Cyclic - P
  13. Hard to remember one letter code - W, Y, K, N, Q, D, E

*Note: Amino acids in parentheses have the indicated character to a limited extent.

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Copyright© Charles S. Gasser 2009, 2013.

Here are some silly mnemonics to help remember some of the amino acids or their one letter abbreviations.

  • Glycine, Gly, G - glycine "glad to be seen" on a test because it is the smallest and easiest to draw.
  • Valine, Val, V - V-shaped. It is the smallest V-shaped structure you can have as a hydrocarbon tail.
  • Leucine, Leu, L - Like valine only Longer.
  • Isoeucine, Leu, L - Isomer of leucine, the only one that is a structural isomer that is still branched.
  • Proline, Pro, P - Like the "Pro Line" in football, proline is sturdy because of the cyclic structure.
  • Threonine, Thr, T - Has a 3-O (Three- O - nine) in the -CH3 and -OH.
  • Cysteine, Cys, C - Sounds like "Sis-teine" which has an S like the sulfur in the cysteine.
  • Methionine, Met, M - Met-thiol (it has a methyl group on a sulfur)
  • Phenylalanine, Phe, F - It's name describes it, a Phenyl group added to Alanine. Sounds like it starts with "F"
  • Tyrosine, Tyr, Y - The phenyl group looks like a "tire" and it has an "O" on it so "tire-O-sine". The base of the phenyl group looks like a "Y"
  • Tryptophan, Trp, W - you can pronounce it "twyptophan" to remember the W. Also the lower part of the ring structure forms a "W" shape
  • Arginine, Arg, R - "Arg"inine "Arg!" I have to draw Arginine! The opposite of glad to be seen. Sounds like the letter "R"
  • Aspartate, Asp, D - Can say "asparDic acid" to remember the "D"
  • Glutamate, Glu, E - "E" comes after "D" aspartate
  • Aparagine, Asn, N - It is Aspartate with an "N" added to it
  • Glutamine, Gln, Q - "Cute"amine (sounds like "Q"), Glutamate with amine added
  • Aparagine, Asn, N - It is Aspartate with an "N" added toi it