A is for ALANINE [poem]

by Greg Crowther

Amino acids are the building blocks from which proteins are made. This poem presents a brief review of the 1-letter abbreviations and structures of the 20 major amino acids found in cells. (There are also 3-letter abbreviations, not shown here.) The poem was written in 1999, published in Biochemical and Molecular Biology Education (BAMBEd) in 2005, and revised in 2015 for Biology/Chemistry 364 at UW-Bothell.

A is for ALANINE, three carbons long;
C is for CYSTEINE, with a sulfhydryl prong.
D is ASPARTATE; it’s lost its H-plus;
GLUTAMATE’s E; it too appears thus.

F, PHENYLALANINE: benzene on board;
GLYCINE, or G, wins the small-size award.
H is for HISTIDINE. What a great buffer!
And water prompts I, ISOLEUCINE, to suffer.

K: LYSINE's high on the pKa scale;
L is for LEUCINE, with its long Y-shaped tail.
M is METHIONINE: sulfury lout,
And N is ASPARAGINE: amide, no doubt.

P: PROLINE flaunts its odd ring like a bride;
Q, GLUTAMINE, is another amide.
R, ARGININE, has four Ns in all.
And S is for SERINE, a petite alcohol.

T is for THREONINE, similar to S;
V is for VALINE. Aliphatic? Why, yes!
W, TRYPTOPHAN: rings at the end,
And Y, TYROSINE, is the kinases' friend.

• MP3

(1) Explain the lines describing histidine, isoleucine, and tyrosine.

(2) A previous version of this poem included the following lines: "D is ASPARTATE, a good proton source,/ And E, GLUTAMATE, is one also, of course." In what way are these lines misleading?

(Answers may be found on the answers page.)