amino acids

Essential amino acids in adult humans: lysine, leucine, isoleucine, methionine, phenylalanine, threonine, tryptophan, and valine.
Additional amino acids essential to children: histidine and arginine.

amino acid chartalaninearginineasparagineaspartic acidcysteineglutamic acidglutamineglycinehistidineisoleucineleucinelysineN-formylmethioninemethioninephenylalanineprolineserinethreoninetryptophantyrosinevaline

External links: Alanine Arginine Asparagine Aspartic acid Cysteine Glutamic acid Glutamine Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Proline Serine Threonine Tryptophan Tyrosine Valine Essential amino acid Protein Peptide Genetic code Isoleucine and valine biosynthesis Leucine biosynthesis

amino acid chart


Non-polar amino acid Ala A RNA code: GCU, GCC, GCA, GCG


Basic amino acid Arg R RNA code: CGU, CGC, CGA, CGG, AGA, AGG


Polar amino acid Asn N RNA code: AAU, AAC

aspartic acid

Acidic amino acid Asp D RNA code: GAU, GAC


Polar amino acid Cys C RNA code: UGU, UGC

glutamic acid

Acidic amino acid Glu E RNA code: GAA, GAG


Non-polar amino acid Gly G RNA code: GGU, GGC, GGA, GGG


Polar amino acid Gln Q RNA code: CAA, CAG


Basic amino acid His H RNA code: CAU, CAC

Histidine's imidazole side chain has a hydrogen-bound nitrogen atom that is slighty acidic and another nitrogen that is slightly basic. The almost neutral pKa of histidine ensures that its charge will change in response to relatively small shifts in cellular pH.

Histidine functions as a co-ordinating ligand in metalloproteins, and at the catalytic site of some enzymes. In catalytic triads, the basic nitrogen of histidine extracts a proton from serine, threonine or cysteine, activating the nitrogen as a nucleophile. In a histidine proton shuttle, histidine rapidly shuttles protons by abstracting a proton onto the basic nitrogen to generate a positively-charged intermediate before passing a proton from the acidic nitrogen. Carbonic anhydrases employ the histidine proton shuttle to rapidly shuttle protons away from a zinc-bound water molecule to quickly regenerate the active form of the enzyme.


Non-polar amino acid Ile I RNA code: AUU, AUC, AUA


Non-polar amino acid Leu L RNA code: UUA, UUG, CUU, CUC, CUA, CUG


Basic amino acid Lys K RNA code: AAA, AAG


N-Formylmethionine (fMet) is an amino acid that is found in all living cells. It is a derivative of the amino acid methionine, in which a formyl group has been added to methionine's amino group (catalyzed by the enzyme transformylase when Met is attached to tRNA.fMet, but not to tRNA.Met).

N-Formylmethionine plays a crucial role in the protein biosynthesis of bacteria, archaea, mitochondria and chloroplasts. Bacteria utilize N-formylmethionine (f-Met) rather than methionine at the N-terminal of the elongating polypeptide chain.

Compare to methionine.

f-Met amino acid RNA code: AUG tRNA.fMet & tRNA.Met


Non-polar amino acid Met M amino acid RNA code: AUG (also stop codon)


Aromatic Non-polar amino acid Phe F RNA code: UUU, UUC


Non-polar amino acid Pro P RNA code: CCU, CCC, CCA, CCG


Polar amino acid Ser S RNA code: UCU, UCC, UCA, UCG, AGU, AGC

Serine is a biosynthetic derivative of glycine, and a biosynthetic precursor of purines and pyrimidines, cysteine, tryptophan, and other metabolites.

Serine is found in the active sites of many enzymes including the serine proteases chymotrypsin and trypsin.

Serine is important in signal transduction because it is phosphorylated by serine/threonine kinases.


Polar amino acid Thr T RNA code: ACU, ACC, ACA, ACG

Threonine is an essential amino acid in humans.

Threonine is important in signal transduction because it is phosphorylated by serine/threonine kinases.


Aromatic Non-polar amino acid Trp W RNA code: UGG


Aromatic Polar amino acid Tyr Y RNA code: UAU, UAC

Tyrosine plays an important role in signal transduction because protein tyrosine kinases and receptor tyrosine kinases can phosphorylate the amino acid within proteins.

Tyrosine is a biosynthetic precursor of the thyroid hormone thyroxine (T4) and triiodothyronine (T3), the pigment melanin, the catecholamine neurotransmitter dopamine and norepinephrine, the neurotransmitter/hormone epinephrine, and in the opium poppy, morphine.


Non-polar amino acid Val V RNA code: GUU, GUC, GUA, GUG
. . . since 10/06/06