The precursor molecules used by a cell's molecular machinery to construct proteins and enzymes. There are twenty (20) amino acids from which all biological tissue is constructed.

Amino Acid	3-Ltr Code	1-Ltr Code	Non/Pol.	S(S)	P?(Y)	e(+/-/)
alanine	Ala	A	N
arginine	Arg	R	P			+
asparagine	Asn	N	P
aspartic acid	Asp	D	P			-
cysteine	Cys	C	P	S
glutamic acid	Glu	E	P			-
glutamine	Gln	Q	P
glycine	Gly	G	N
histidine	His	H	P			+
isoleucine	Ile	I	N
leucine	Leu	L	N
lysine	Lys	K	P			+
methionine	Met	M	N	S
phenylalanine	Phe	F	N
proline	Pro	P	N
serine	Ser	S	P		Y
threonine	Thr	T	P		Y
tryptophan	Trp	W	N
tyrosine	Tyr	Y	P		Y
valine	Val	V	N

Columns: Amino Acid: Full name of the amino acid 3-Ltr Code: Three letter code for the amino acid 1-Ltr Code: One letter code for the amino acid Non/pol. An 'N' in this column denotes that the amino acid is Nonpolar (hydrophobic), otherwise it is Polar (hydrophilic) S An 'S' in the column indicates that the amino acid contains sulfur. P? A 'Y' (yes) in this column indicates that the amino acids can be phosphorylated e(+/-/) Indicates the electrical charge, if any, of the amino acid

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Sources and Resources

• The Chemistry of Amino Acids