Amacidos Nemotecnia

E-mail address: vmezl@uottawa.ca (V.A. Mezl).

Biochemistry and Molecular Biology Education 29 (2001) 66}70

The AAA amino acid list a mnemonic derivation of the structures and

properties of the amino acids

Vasek A. Mezl

Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa,

Ont. Canada, K1H 8M5

Abstract

A rhymed presentation of the amino acids, consisting of one line per amino acid, gives the structures of the amino acids, their

nomenclature, abbreviations, pKs, basic chemistry, dietary requirements and the characteristics of the peptide bond.
2001

IUBMB. Published by Elsevier Science Ltd. All rights reserved.

1. Introduction

Almost all the life sciences at some point involve the

amino acids and in day-to-day lab work one often needs

semi-quantitative amino acid data that cannot be derived

from a recollection of general structures. While most

biochemistry courses cover these compounds, the wealth

of information and the only occasional need for it means

that little is retained over the long term.

Since rhymed jingles and relationships are remembered

over long periods, a rhymed presentation of the

amino acids has been devised that not only allows one to

learn and retain the structure of the amino acids, but this

mnemonic also provides information about the amino

acids and their relationship to other body components.

The order in which these amino acids are presented,

referred to as the AAA amino acid list, can be used to

derive key metabolic relationships and several lists of

numerical data related to the amino acids. This article

presents the mnemonic and shows how to use the imagery

raised by the words to derive the structures and

some basic chemical properties.

2. Instructions

In the mnemonic, the names of amino acids are in italic

type and the three letter abbreviations are double underlined.

The one letter abbreviations are in bold type; for

the "rst 11 amino acids they are the "rst letter of the

name and for the rest of the list they are the "rst letter of

each line. Essential amino acids are identi"ed by lines

containing the word give or get (underlined in the text);

one has to give them in the diet or get them in the diet for

normal health. Vertical spacing divides the text into

sections that are used for the derivation of the structures

(endnotes), for the presentation of metabolic relationships

(article in preparation), for the generation of numerical

data (see Section 1) and for the rapid retrieval of

speci"c information about an amino acid (Section 4). The

number of words in each line is equal to the number of

carbons in each amino acid. This feature can be used to

verify several structures and for quickly calculating molecular

weights and other characteristics. Other topics

that can be derived from these lines are underlined in the

detailed explanations provided as endnotes. Fig. 1 shows

the structures of the amino acids in the order in which

they are developed using bold type to highlight the new

structural element that is added at each line.

1470-8175/01/$20.00
2001 IUBMB. Published by Elsevier Science Ltd. All rights reserved.

PII: S 1 4 7 0 - 8 1 7 5 ( 0 1 ) 0 0 0 1 3 - 3

3. The AAA mnemonic

AminoP, Acid
, Alpha hydrogen;

All three on one carbon. [1]

When my forearm comes from the end and my "ngers are

AAA;

-D-sugars are my right hand, amino acids are a Left

hand away. [2]

Glycine's symmetrical; [3]

Alanine's methyl's typical. [4]

Alcohol addition's Serine;

Another methyl gives TThreonine. [5]

Twice methylated alanine gives Valine;

but stretched homovaline unfortunately gives Leucine;

[6]

Isoleucine gives another rare logical scoop; [7]

Proline's envelope freezes amino group. [8]

Sensitive sulfhydryl's Cysteine; [9]

Homocysteine methylation continuously gives

Methionine. [10]

Histidine's two nitrogen twingling imidazole star; [11]

Without its closest nitrogen, buds a benzene, giving

Trypptophan's indole handlebar. [12]

For Phenylalanine we get a weak  logical scoop;

Yet ¹yrosine's just phenylalanine with A para alcohol

group. [13]

Dicarboxyl means negative Aspartic; [14]

Not amide, Asparagine's Biotypic; [15]

Extra methylene means Glutamic's homoaspartic;

Quasi homoasparagine, Glutamine's still Zwitterionic.

[16]

Key six aliphatic amine gives Lysine; [17]

Resonant guanidino on "ve begets Arginine. [18]

4. One line summary

For the rapid recall of the order or of a speci"c section

of the AAA list, a possibly life saving phrase sequentially

gives the "rst word (in italics) or the idea (underlined

below) of each section: `Glass-in Alcohol Twice: Su!er His

Negative Charges!a On the one hand, this line warns that

if one drinks two alcoholic drinks before driving, one will

be charged with driving under the in#uence of alcohol in

North America and on the other hand it recalls the order

of the various sections if one interprets suwer as sulphur,

negative as the charge on the R group and charges as the

other possible charge on the R group. Twice identi"es

the "rst section that is twice as long as most sections and

one can note that such a four line section is then found

twice more. This summary presents the amino acids as

seven groups based on the characteristics of their side

chains: small, alcohol containing, aliphatic, sulfur containing,

rings with double bonds, acids (and their amides)

and basic side chains. The lecturer should present these

groups by using the "ngers of both hands to list the

amino acid pairs. Students should be encouraged to

summarize the amino acids on their "ngers in this manner

as this will prevent them from forgetting a category of

amino acids.

5. Deriving the peptide bond from the AAA mnemonic

One mispronunciation and one word replacement

change the de"nition of an amino acid into a line that

describes the peptide bond: AminoP, Acid
, Awful hydrogen,

All three on one plane. The "rst two words and

arrows, highlight the fact that the peptide bond is completely

uncharged by pointing out that when the amino

group is joined to the carboxyl group (AminoP, Acid) all

the charges are dropped (
). This is further emphasized

by stating that the hydrogen is now Awful since it often

fools students into thinking that it is charged. To relate

this to an earlier topic, the lecturer can review the di!erence

between an amide [15] and an amine [1,17]. The

"rst arrow also illustrates the fundamental convention

that protein sequences are written from the amino terminus

to the carboxyl terminus. As the students are shown

that all the bonds of the amino group and of the carboxyl

group are in the same plane (All three on one plane), the

description can be simpli"ed to the three words,

AminoP Acid
plane. When the trans con"guration of

the peptide bond is discussed, the proline description [8]

can be used to explain why Pro can be found in the cis

con"guration.

The proximity e!ects that alter the pKs of the groups

found on free amino acids [1] cannot occur in proteins

and the groups found at the two termini will have altered

ionization constants. The trend can be recalled by thinking

that as amino acids approach each other, the two pKs

approach each other. The number of lines indicated by

each arrows gives an estimate of this di!erence in pKs.

With a pK of about 8, the amino terminus is one order of

magnitude (the horizontal arrow indicates one line) more

acidic than a AAA amino group [1]. The carboxyl group

of a protein (pK+4) is two orders of magnitude (the

vertical arrow indicates two lines) more basic than the

AAA carboxyl group; it is comparable to an aliphatic

carboxyl group [1].

V.A. Mezl / Biochemistry and Molecular Biology Education 29 (2001) 66}70 67

Fig. 1. Derivation of the structures of the amino acid using the AAA

mnemonic. The structures are derived going from left to right as

described in the text. The one letter abbreviation and each new element

of structure are shown in bold type. These wordprocessor generated

structures can be easily duplicated and modi"ed with a word processor

to write out entire pathways (the WordPerfect
9 "le for Fig. 1 can be

obtained from the author at vmezl@uottawa.ca).

6. Analysis of the amino acids

The "rst word of the amino acid de"nition gives the

group that is the principle of both the separation and the

measurement of the amino acids. The amino group binds

to the ion exchange column of

...