Amino Acid Reference Chart

Amino acids are the building blocks that make up all proteins, polypeptides and peptides. Each amino acid consists of a central carbon, known as the α-carbon, to which an amino group (-NH₂), an acidic carboxyl group (-COOH) and an organic side chain (-R group) are bound. The R group, which differs for each amino acid, will determine its structure, polarity and pH.

Refer to chart below to explore structures, properties and types for each of the 20 standard amino acids.

Amino Acids ▲ ▼	Structure ▲ ▼	Abbr (3) ▲ ▼	Abbr (1) ▲ ▼	Enzymes ▲ ▼	Products ▲ ▼	Codon ▲ ▼	Class ▲ ▼	Hydrophobicity (pH 7) ▲ ▼	Freq. in Proteins (max. 10) ▲ ▼	pKa ▲ ▼	pI ▲ ▼	Chemical formula ▲ ▼	Molar mass ▲ ▼	IUPAC name ▲ ▼	Other names ▲ ▼	CAS Number ▲ ▼	InChI ▲ ▼	SMILES ▲ ▼	Appearance ▲ ▼	Density ▲ ▼	Melting point ▲ ▼	Solubility in water ▲ ▼
Alanine		Ala	A	Alanine Aminotransferase	13803, 13802, 13826, 13825	GCT, GCC, GCA, GCG	Aliphatic	41	7.5	2.34	6.00	C3H7NO2	89.094	Alanine	2-Aminopropanoic acid	338-69-2; 56-41-7; 302-72-7;	InChI=1S/C2H4NH2COOH/c1-2(4)3(5)6/h2H,4H2,1H3,...	O=C(O)C(N)C	white powder	1.424 g/cm3	258 °C (496 °F; 531 K) (sublimes)	167.2 g/L (25 °C)
Arginine		Arg	R	Arginase	-	CGT, CGC, CGA, CGG, AGA, AGG	Basic	-14	5.0	2.17	10.76	C6H14N4O2	174.204	(S)-2-Amino-5-guanidinopentanoic acid	2-Amino-5-guanidinopentanoic acid	7200-25-1; 157-06-2; 74-79-3	InChI=1S/C6H14N4O2/c7-4(5(11)12)2-1-3-10-6(8)9...	NC(CCCNC(N)=N)C(O)=O	White crystals	1.5±0.1 g/cm3	260 °C; 500 °F; 533 K	14.87 g/100 mL (20 °C)
Asparagine		Asn	N	Asparagine Synthetase; Asparaginase	-	AAT, AAC	Amidic	-28	4.5	2.02	5.41	C4H8N2O3	132.119	Asparagine	2-Amino-3-carbamoylpropanoic acid	70-47-3	InChI=1S/C4H8N2O3/c5-2(4(8)9)1-3(6)7/h2H,1,5H2...	O=C(N)C[C@H](N)C(=O)O	white crystals	1.543 g/cm3	234 °C (453 °F; 507 K)	2.94 g/100 mL
Aspartic acid		Asp	D	Aspartic Protease; Aspartic Proteinase	13828, 13827, 13480	GAT, GAC	Acidic	-55	5.0	1.88	2.77	C4H7NO4	133.103	2-Aminobutanedioic acid	Aminosuccinic acid; Asparagic acid; Asparagini...	617-45-8; 56-84-8; 1783-96-6	InChI=1S/C4H7NO4/c5-2(4(8)9)1-3(6)7/h2H,1,5H2,...	O=C(O)CC(N)C(=O)O	colourless crystals	1.7 g/cm3	270 °C (518 °F; 543 K)	4.5 g/L
Cysteine		Cys	C	Cysteine Protease; Cysteine Peptidase	-	TGT, TGC	Sulfur-containing	49	2.0	1.96	5.07	C3H7NO2S	121.150	Cysteine	2-Amino-3-sulfhydrylpropanoic acid	52-90-4; 52-89-1	InChI=1S/C3H7NO2S/c4-2(1-7)3(5)6/h2,7H,1,4H2,(...	C([C@@H](C(=O)O)N)S	white crystals or powder	1.3±0.1 g/cm	240 °C (464 °F; 513 K) decomposes	soluble
Glutamic acid		Glu	E	Glutamic Acid Decarboxylase	10054, 11302	GAA, GAG	Acidic	-31	6.5	2.19	3.22	C5H9NO4	147.130	2-Aminopentanedioic acid	2-Aminoglutaric acid	L isomer: 56-86-0; racemate: 617-65-2; D isome...	InChI=1S/C5H9NO4/c6-3(5(9)10)1-2-4(7)8/h3H,1-2...	l isomer: C(CC(=O)O)[C@@H](C(=O)O)N	white crystalline powder	1.4601 (20 °C)	199 °C (390 °F; 472 K) decomposes	7.5 g/L (20 °C)
Glutamine		Gln	Q	Glutamine Synthetase	11302	CAA, CAG	Amidic	-10	4.0	2.17	5.65	C5H10N2O3	146.146	Glutamine	L-Glutamine; (levo)glutamide; 2,5-Diamino-5-ox...	56-85-9	InChI=1S/C5H10N2O3/c6-3(5(9)10)1-2-4(7)8/h3H,1...	O=C(N)CCC(N)C(=O)O	White crystalline powder	1.47 g/cm3 (20 °C)	decomposes around 185°C	soluble
Glycine		Gly	G	Glycine Decarboxylase Complex; Glycine Hydroxymethyltransferase; Glycine N-Methyltransferase	395, 396	GGT, GGC, GGA, GGG	Aliphatic	0	7.0	2.34	5.97	C2H5NO2	75.067	2-aminoacetic acid	2-Aminoethanoic acid, Glycocoll	56-40-6	InChI=1S/C2H5NH2/c3-1-2(4)5/h1,3H2,(H,4,5); Ke...	C(C(=O)O)N	White solid	1.1607 g/cm3	233 °C (451 °F; 506 K) (decomposition)	24.99 g/100 mL (25 °C)
Histidine		His	H	Histidine Ammonia-Lyase; Histidine Decarboxylase; Histidine Acid Phytases	-	CAT, CAC	Basic	8	2.0	1.82	7.59	C6H9N3O2	155.157	Histidine	2-Amino-3-(1H-imidazol-4-yl)propanoic acid	71-00-1	InChI=1S/C6H9N3O2/c7-5(6(10)11)1-4-2-8-3-9-4/h...	O=C([C@H](CC1=CNC=N1)N)O	colourless crystals	1.4±0.1 g/cm3	287 °C	4.19g/100g @ 25 °C
Isoleucine		Ile	I	L-Isoleucine 4-Hydroxlase; Isoleucine 2-Epimerase	-	ATT, ATC, ATA	Aliphatic	99	5.5	2.36	6.02	C6H13NO2	131.175	Isoleucine	(2S,3S)-2-amino-3-methylpentanoic acid	73-32-5	InChI=1S/C6H13NO2/c1-3-4(2)5(7)6(8)9/h4-5H,3,7...	CC[C@H](C)[C@@H](C(=O)O)N	waxy, shiny crystals	?1.0±0.1 g/cm3	285.5 °C	soluble
Leucine		Leu	L	Leucine Dehydrogenase; Leucine Aminotransferase; Leucine Transaminase; Leucine Deacylase; Leucine Aminopeptidase	13445	CTT, CTC, CTA, CTG, TTA, TTG	Aliphatic	97	9.0	2.36	5.98	C6H13NO2	131.175	Leucine	2-Amino-4-methylpentanoic acid	61-90-5	InChI=1S/C6H13NO2/c1-4(2)3-5(7)6(8)9/h4-5H,3,7...	CC(C)C[C@@H](C(=O)O)N	white crystals	1.17 g/cm3 at 20 °C	293 °C	soluble
Lysine		Lys	K	Lysine a-Ketoglutarate Reductase; I-Lysine Monooxygenase; I-Lysine Decarboxylase; Lysine Oxidase; Lysine 2,3-Aminomutase	15255	AAA, AAG	Basic	-23	6.0	2.18	9.74	C6H14N2O2	146.190	(2S)-2,6-Diaminohexanoic acid (L-lysine); (2R)...	Lysine, D-Lysine, L-lysine, LYS, h-Lys-OH	70-54-2; 56-87-1; 923-27-3	InChI=1S/C6H14N2O2/c7-4-2-1-3-5(8)6(9)10/h5H,1...	NCCCCC(N)C(=O)O	colourless crystals	1.1±0.1 g/cm 3	224.5 °C	1.5 kg/L
Methionine		Met	M	Methionine Synthase; Methionine Aminopeptidase	-	ATG	Sulfur-containing	74	2.5	2.28	5.74	C5H11NO2S	149.210	Methionine	2-amino-4-(methylthio)butanoic acid	59-51-8; 63-68-3 (L-isomer); 348-67-4 (D-isomer)	InChI=1S/C5H11NO2S/c1-9-3-2-4(6)5(7)8/h4H,2-3,...	CSCC[C@H](N)C(=O)O	White crystalline powder	1.340 g/cm3	281 °C (538 °F; 554 K) decomposes	soluble
Phenylalanine		Phe	F	Phenylalanine Hydroxylase	-	TTT, TTC	Aromatic	100	4.0	1.83	5.48	C9H11NO2	165.192	(S)-2-Amino-3-phenylpropanoic acid	L-Phenylalanine	150-30-1; 63-91-2	InChI=1S/C9H11NO2/c10-8(9(11)12)6-7-4-2-1-3-5-...	N[C@@H](CC1=CC=CC=C1)C(O)=O	White crystalline powder	1.34 g/cm3 at 20 °C	283 °C	soluble
Proline		Pro	P	Proline Dehydrogenase; Proline 3-Hydroxlase	-	CCT, CCC, CCA, CCG	Aliphatic	-46	5.0	1.99	6.30	C5H9NO2	115.132	Proline; Pyrrolidine-2-carboxylic acid	L-Proline	609-36-9; 344-25-2 (R); 147-85-3 (S)	InChI=1S/C5H9NO2/c7-5(8)4-2-1-3-6-4/h4,6H,1-3H...	OC(=O)C1CCCN1	Transparent crystals	1.35-1.38 g/cm3 at 25 °C	205 to 228 °C (401 to 442 °F; 478 to 501 K)	soluble
Serine		Ser	S	Serine Protease; Serine Endopeptidase; Serine Racemase	-	TCT, TCC, TCA, TCG, AGT, AGC	Hydroxylic	-5	7.5	2.21	5.68	C3H7NO3	105.093	Serine	2-Amino-3-hydroxypropanoic acid	56-45-1 (L-); 302-84-1 (DL-); 312-84-5 (D-)	InChI=1S/C3H7NO3/c4-2(1-5)3(6)7/h2,5H,1,4H2,(H...	C([C@@H](C(=O)O)N)O	white crystals or powder	1.603 g/cm3 (22 °C)	246 °C (475 °F; 519 K) decomposes	soluble
Threonine		Thr	T	Threonine Ammonia-Lyase; Threonine Deaminase; Threonine Dehydratase; Threonine Aldolase	-	ACT, ACC, ACA, ACG	Hydroxylic	13	6.0	2.09	5.60	C4H9NO3	119.120	Threonine	2-Amino-3-hydroxybutanoic acid	80-68-2; 72-19-5 (L-isomer)	InChI=1S/C4H9NO3/c1-2(6)3(5)4(7)8/h2-3,6H,5H2,...	C[C@H]([C@@H](C(=O)O)N)O	colourless crystals	1.3±0.1 g/cm 3	256 °C (decomposes)	(H2O, g/dl) 10.6(30°),14.1(52°),19.0(61°)
Tryptophan		Trp	W	Tryptophan Synthase; Tryptophan 2,3-Dioxygenase	8B1012, 8B1011, 8A1012, 8A1011	TGG	Aromatic	97	1.5	2.83	5.89	C11H12N2O2	204.229	Tryptophan; (2S)-2-amino-3-(1H-indol-3-yl)prop...	2-Amino-3-(1H-indol-3-yl)propanoic acid	73-22-3	InChI=1S/C11H12N2O2/c12-9(11(14)15)5-7-6-13-10...	c1ccc2c(c1)c(c[nH]2)C[C@@H](C(=O)O)N	White crystalline powder	1.4±0.1 g/cm3	290.5 °C	Soluble: 0.23 g/L at 0 °C, 11.4 g/L at 25 °C
Tyrosine		Tyr	Y	Tyrosinase; Tyrosine Hydroxylase; Tyrosine Kinase; Tyrosine Decarboxylase	8B0037, 8B0038, 8B0039, 8A0037, 8A0038, 8A0039, 8B0592, 8A0592, 11312, 11311, 8C0382,	TAT, TAC	Aromatic	63	3.5	2.20	5.66	C9H11NO3	181.191	(S)-Tyrosine	L-2-Amino-3-(4-hydroxyphenyl)propanoic acid	60-18-4	InChI=1S/C9H11NO3/c10-8(9(12)13)5-6-1-3-7(11)4...	N[C@@H](Cc1ccc(O)cc1)C(O)=O	white crystals	1.46 g/cm3 at 20 °C	343 °C	.0453 g/100 mL
Valine		Val	V	L-Valine Dehydrogenase	-	GTT, GTC, GTA, GTG	Aliphatic	76	6.5	2.32	5.96	C5H11NO2	117.148	Valine	2-Amino-3-methylbutanoic acid	0516-06-03; 72-18-4 (L-isomer); 640-68-6 (D-is...	InChI=1S/C5H11NO2/c1-3(2)4(6)5(7)8/h3-4H,6H2,1...	CC(C)[C@@H](C(=O)O)N	white crystalline solid	1.316 g/cm3	298 °C (568 °F; 571 K) (decomposition)	soluble

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References

This online tool may be cited as follows

MLA	"Quest Database™ Amino Acid Reference Chart." AAT Bioquest, Inc., 23 Dec. 2024, https://www.aatbio.com/data-sets/amino-acid-reference-chart-table.
APA	AAT Bioquest, Inc. (2024, December 23). Quest Database™ Amino Acid Reference Chart. AAT Bioquest. https://www.aatbio.com/data-sets/amino-acid-reference-chart-table.
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Amino Acid Reference Chart

References

This online tool may be cited as follows

MLA

APA