Today I started reviewing material from the MCAT so that when med school arrives in a couple of months, I can hit the ground running. I’m not a fan of memorizing things, but there are a few places where it can’t be helped. Knowing the amino acids is a good example.
I have three acronyms to help me remember the name of each amino acid. A couple of them also prompt me to recall the amino acid’s structure. Each acronym represents a group of amino acids, and each group is based on the electron character of the molecule’s side chain. Note that the acronyms use the amino acids’ one-letter abbreviations:
Non-polar side chains: “Grandma Always Visits London In May For Winston’s Party” (G, A, V, L, I, M, F, W, P)
Polar side chains: “Santa’s Team Crafts New Quilts Yearly” (S, T, C, N, Q, Y)
Electrically charged side chains: “Dragons Eat Knights Riding Horses” (D, E, K, R, H)
Although these tools may be a good fit for you, memorizing the amino acids will still take work. I recommend getting a few sheets of paper walking through these four steps:
First, write down the letter sequence of each acronym in separate areas of the page, leaving space to draw each amino acid. Say the acronym aloud to yourself as you go along. (At first, you’ll also want to write down the full name and three-letter abbreviation of each amino acid. Later, once you know the names of all 20 molecules, you’ll probably be safe just writing the three-letter code.)
Second, draw the amino acid fundamental structure (the alpha carbon, amino group, and carboxylic acid group) above each letter. You can either show this structure as either a Fischer projection (as shown in the image above) or as a stereochemical figure. Remember that the amino and carboxyl groups are ionized at pH 7, as are the electrically charged side chains.
Third, attached to each fundamental structure, draw the appropriate side chain. Think aloud as you draw each side chain–it will help you to remember better. Pay attention to the order of the acronym and changes in structure as you move from one side chain to the next.
Finally, rinse and repeat. Do this exercise once per day for a week, then once every other day for a week, and finally one or two times weekly going forward. Later on, try drawing the side chains in reverse or random order for an extra challenge.
Okay, now that we have a game plan, let’s take a closer look at those the acronyms:
Non-polar side chains:
“Grandma Always Visits London In May For Winston’s Party”
- Glycine, Gly, G
- Alanine, Ala, A
- Valine, Val, V
- Leucine, Leu, L
- Isoleucine, Ile, I
- Methionine, Met, M
- Phenylalanine, Phe, F
- Tryptophan, Trp, W
- Proline, Pro, P
To remember that that this is the acronym for non-polar side chains, recall that London, England, is not located near the Earth’s poles. Also, it may help you to associate London with Winston Churchill (the United Kingdom’s prime minister during World War II) and, by extension, with May 8th (Victory in Europe Day, which celebrates the formal surrender of Nazi Germany to the Allies).
The troublemakers in the non-polar group are phenylalanine (F) and tryptophan (W). Of course, phenylalanine’s one-letter abbreviation should be relatively easy to recall because the first two letters, “ph”, are pronounced as if they were an “F”. Meanwhile, a trick to remember tryptophan’s abbreviation is to imagine a sideways letter W formed by several of the bonds in the side chain’s joined five- and six-member rings.
Polar side chains:
“Santa’s Team Crafts New Quilts Yearly”
- Serine, Ser, S
- Threonine, Thr, T
- Cysteine, Cys, C
- Asparagine, Asn, N
- Glutamine, Gln, Q
- Tyrosine, Tyr, Y
To remember that this is the acronym for polar side chains, all you need to do is ask a five year-old where Santa and his team of elves live–at the North Pole, of course! (My mom is really into quilting and sewing, so it’s helpful for me to associate quilts with Christmas gifting.)
The troublemakers in the polar group are asparagine (N), glutamine (Q), and tyrosine (Y). One way to deal with the first two is to skip ahead to the trick for remembering aspartate and glutamate (see the end of this post for a note on asparagine and glutamine). Meanwhile, I remember that tyrosine has the abbreviation Y because that letter is the second in the full name, and because if the side chain is drawn facing downward, two of the bonds in the phenyl ring and the bond with the hydroxyl group can form an imaginary Y.
Cysteine is also a bit tricky, but only because the other official way of spelling the name, “cystine” refers to amino acids’ oxidized form.
Electrically charged side chains:
“Dragons Eat Knights Riding Horses”
- Aspartate, Asp, D
- Glutamate, Glu, E
- Lysine, Lys, K
- Arginine, Arg, R
- Histidine, His, H
By process of elimination, you’ll know that this acronym refers to the remaining group of amino acids. Like those pesky dragons, nearly every molecule here is a troublemaker: aspartate (D), glutamate (E), lysine (K), and arginine (R).
There are two eating-themed tricks that I use to remember aspartate (D) and glutamate (E). First, I associate the suffix “-ate” with the idea of dragons eating. Second, when I look at the two amino acids’ abbreviations, “Asp” and “Glu”, I think of the phrase “Aspiring Gluttons”. Meanwhile, for lysine (K), I just remember that L follows K in the alphabet. And arginine’s one-letter abbreviation should be relatively easy to recall because the first two letters, “ar”, are pronounced like the name of the letter R.
Note on asparagine and glutamine:
Asparagine (N) and glutamine (Q) are identical to aspartate (D) and glutamate (E), except that the former two have an amino group where the latter two have a negatively charged oxygen. It’s helpful that the three-letter abbreviations for asparagine (N) and glutamine (Q) are Asn and Gln, respectively–the fact that both contain the letter “n” reminds me of the nitrogen atom found in their amino side chains.