List of standard protein amino acids

Standard amino Acids (English:amino acids) or protein amino acids (proteinogenic amino acids), It is a total of 20 amino acids used in biological cells to synthesize proteins. This list mainly describes its name, marking method, structure and nature. Also included are the secondary encoding of amino acids, selenium cysteine and pyrrole lysine, respectively, with the usual termination codon UGA and UAG encoding, appearing in a few proteins. See 21st and 22nd amino acids .

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• 1 names and symbols
• 2 Structure
• 3 main chemical properties
• 4 Branched Nature
• 5 gene expression and biochemistry
• 6 References

Name and Symbol

The following table shows each Chinese name with English name, three letter symbol and one letter symbol. (* for secondary coding of amino acids)

Chinese name	English name	Short Write	Abbreviations
Propionic acid	Alanine	A	Ala
Phenylalanine (L-alanine)	Phenylalanine	F	Phe
Cysteine	Cysteine	C	Cys
Selenium cysteine *	Selenocysteine	U	Sec
Aspartic acid	Aspartic acid/aspartate	D	Asp
Aspartic amide	Asparagine	N	Asn
Glutamate	Glutamic acid/glutamate	E	Glu
Ammonium glutamine	Glutamine	Q	Gln
Glycine	Glycine	G	Gly
Histidine	Histidine	H	His
Leucine	Leucine	L	Leu
ISO-leucine	Isoleucine	I	Ile
Lysine	Lysine	K	Lys
Pyrrole lysine *	Pyrrolysine	O	Pyl
Methionine	Methionine	M	Met
L-Proline	Proline	P	Pro
L-Arginine	Arginine	R	Arg
Serine	Serine	S	Ser
Threonine	Threonine	T	Thr
L-Valine	Valine	V	Val
Tryptophan	Tryptophan	W	Trp
Tyrosine	Tyrosine	Y	Tyr

In addition, there are some three-letter or single-letter symbols that can be used to denote undefined abbreviations:

• ASX, B can represent aspartic acid (ASP, D) or aspartic amide (ASN, N).
• GLX, z may represent glutamic acid (Glu, E) or glutamine (Gln, Q).
• Xle, J may represent Leucine (Leu, L) or isoleucine (Ile, I).
• Xaa (also with UNK), X may represent any amino acid or unknown amino acid.

structure

The following is the structure and representation of the 20 amino acids that the standard genetic code uses to directly synthesize proteins.

• L-alanine
  (ala/a)

• L-arginine
  (ARG/R)

• L-aspartic amide
  (asn/n)

• L-aspartic acid
  (ASP/D)

• L-cysteine
  (CYS/C)

• L-Glutamic acid
  (glu/e)

• L-Glutamine
  (gln/q)

• Glycine
  (gly/g)

• L-histidine
  (his/h)

• L-isoleucine
  (ile/i)

• L-leucine
  (LEU/L)

• L-lysine
  (lys/k)

• L-methionine
  (met/m)

• L-phenylalanine
  (phe/f)

• L-proline
  (pro/p)

• L-serine
  (SER/S)

• L-threonine
  (thr/t)

• L-Tryptophan
  (trp/w)

• L-tyrosine
  (tyr/y)

• L-valine
  (val/v)

• L-Selenium cysteine
  (sec/u)

• L-Pyrrole lysine
  (pyl/o)

Main chemical properties

The following molecular weight is the average of the abundance of isotopes in nature based on each element. In addition, due to the formation of peptide bonds, a water molecule is reduced, so the molecular weight of the single amino acid in the protein, less than the table value 18.01524 Da.

Amino Acids	Molecular Weight (Da)	PI	pK1 (Α-cooh)	pK2 (Α-+NH3)
Propionic acid	89.09404	6.01	2.35	9.87
Cysteine	121.15404	5.05	1.92	10.70
Selenium-cysteine	169.06
Aspartic acid	133.10384	2.85	1.99	9.90
Glutamate	147.13074	3.15	2.10	9.47
Phenylalanine (L-alanine)	165.19184	5.49	2.20	9.31
Glycine	75.06714	6.06	2.35	9.78
Histidine	155.15634	7.60	1.80	9.33
ISO-leucine	131.17464	6.05	2.32	9.76
Lysine	146.18934	9.60	2.16	9.06
Pyrrole lysine	255.31
Leucine	131.17464	6.01	2.33	9.74
Methionine	149.20784	5.74	2.13	9.28
Aspartic amide	132.11904	5.41	2.14	8.72
L-Proline	115.13194	6.30	1.95	10.64
Ammonium glutamine	146.14594	5.65	2.17	9.13
L-Arginine	174.20274	10.76	1.82	8.99
Serine	105.09344	5.68	2.19	9.21
Threonine	119.12034	5.60	2.09	9.10
L-Valine	117.14784	6.00	2.39	9.74
Tryptophan	204.22844	5.89	2.46	9.41
Tyrosine	181.19124	5.64	2.20	9.21

Branched chain Properties

The pka values in the following list may differ from those of amino acids within the protein.

the of the aliphatic group

Amino Acids	branched	Water Repellent	PKa	Polarity	charge	Aromatic Family Or	van der Waals radius
Propionic acid	-ch3	X	-	-	-	-	67
Cysteine	-ch2sh	X	8.18	-	Acid	-	86
Selenium-cysteine	-ch2seh	X	5.73	-	-	-
Aspartic acid	-ch2cooh	-	3.90	X	Acid	-	91
Glutamate	-ch2ch2cooh	-	4.07	X	Acid	-	109
Phenylalanine (L-alanine)	-ch2c6h5	X	-	-	-	Aromatic nature	135
Glycine	-H	-	-	-	-	-	48
Histidine	-ch2-c3h3n2	-	6.04	X	Weakly alkaline	Aromatic nature	118
ISO-leucine	-ch (CH3) Ch2ch3	X	-	-	-	Fat Sex	124
Lysine	-(CH2) 4NH2	-	10.54	X	Alkaline	-	135
Pyrrole lysine	-c12h21n3o3
Leucine	-CH2CH (CH3) 2	X	-	-	-	Fat Sex	124
Methionine	-ch2ch2sch3	X	-	-	-	-	124
Aspartic amide	-ch2conh2	-	-	X	-	-	96
L-Proline	-ch2ch2ch2-	X	-	-	-	-	90
Ammonium glutamine	-ch2ch2conh2	-	-	X	-	-	114
L-Arginine	-(CH2) 3nh-c (NH) NH2	-	12.48	X	Alkaline	-	148
Serine	-ch2oh	-	-	X	-	-	73
Threonine	-ch (OH) CH3	-	-	X	Weakly acidic	-	93
L-Valine	-ch (CH3) 2	X	-	-	-	Fat Sex	105
Tryptophan	-ch2-c8h6n	X	-	-	-	Aromatic nature	163
Tyrosine	-ch2-c6h4oh	X	10.46	X	-	Aromatic nature	141

gene expression and biochemistry
of

Amino Acids	Short Write	Abbreviations	codon	in the protein Frequency of occurrence (%)	human necessity
Off-amino acid	K	Lys	AAA, AAG	5.9	X
Aspartic amide	N	Asn	AAU, AAC	4.3	-
Threonine	T	Thr	ACU, ACC, ACA, ACG	5.9	X
Methyl-L-methionine	M	Met	The	2.3	X
ISO-leucine	I	Ile	AUU, AUC, AUA	5.3	X
Ammonium glutamine	Q	Gln	CAA, CAG	4.2	-
Histidine	H	His	CAU, CAC	2.3	-
L-Proline	P	Pro	CCU, CCC, CCA, CCG	5.2	-
L-Arginine	R	Arg	CGU, CGC, CGA, CGG, AGA, AGG	5.1	-
Glutamate	E	Glu	GAA, GAG	6.3	-
Aspartic acid	D	Asp	GAU, GAC	5.3	-
Propionic acid	A	Ala	GCU, GCC, GCA, GCG	7.8	-
Glycine	G	Gly	Ggu, GGC, GGA, GGG	7.2	-
L-Valine	V	Val	GUU, GUC, GUA, GUG	6.6	X
Terminating encoding	-	Term	UAA, UAG, UGA	-	-
Pyrrole lysine	O	Pyl	UAG
Tyrosine	Y	Tyr	Uau, UAC	3.2	-
Serine	S	Ser	UCU, UCC, UCA, UCG, AGU, AGC	6.8	-
Selenium-cysteine	U	Sec	UGA		-
Tryptophan	W	Trp	Ugg	1.4	X
Cysteine	C	Cys	Ugu, UGC	1.9	-
Leucine	L	Leu	UUA, Uug, Cuu, CUC, CUA, CUG	9.1	X
Phenylalanine (L-alanine)	F	Phe	UUU, Uuc	3.9	X

Reference Documents

• Nelson, David L.; Cox, Michael M. Lehninger Principles of Biochemistry 3rd ed. Worth Publishers. ISBN 1-57259-153-6.
• Kyte, J.; Doolittle, R. F. A simple method for displaying the hydropathic character of a protein. J. Mol. Biol. 1982, 157 (1): 105–132. PMID 7108955.

List of standard protein amino acids