Amino acids

Dr Daniel J Bell et al.

Amino acids are the monomeric building blocks of proteins. Amino acids concatenate into chains, which are arbitrarily divided into peptides, polypeptides, or proteins according to chain length. Generally, chains of 10 or fewer amino acids are deemed to be peptides, chain length from 10-100 are polypeptides, and greater than ~100 amino acids are called proteins. 

Structure

All amino acids (except proline) consist of a carboxl (-COOH) group and an amino (-NH2) group, with varying side chains.

Proline is chemically strictly an imino acid, which have an imino (>C=NH) group, instead of an amino group, although for biological usage it is counted as an amino acid.

List of amino acids

Essential vs non-essential

Essential amino acids cannot be synthesised by the cells, and therefore must be obtained from the diet.
Conversely the non-essential amino acids can be made by the body and therefore are not mandatory constituents of a balanced diet.

The list of amino acids has the full name of the amino acid, and in parentheses the standard three letter code and single letter code.

Essential amino acids
  • valine (Val, V)
  • leucine (Leu, L)
  • isoleucine (Ile, I)
  • threonine (Thr, T)
  • methionine (Met, M)
  • phenylalanine (Phe, F)
  • tryptophan (Trp, W) 
  • lysine (Lys, K)
  • histidine (His, H)
Non-essential amino acids
  • glycine (Gly, G)
  • alanine (Ala, A)
  • serine (Ser, S)
  • cysteine (Cys, C)
  • tyrosine (Tyr, Y)
  • aspartic acid (Asp, D)
  • asparagine (Asn, N)
  • glutamine (Gln, Q)
  • glutamic acid (Glu, E)
  • proline (Pro, P)
  • arginine (Arg, R)
  • selenocysteine (Sec, U)
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Article information

rID: 64109
Section: Pathology
Synonyms or Alternate Spellings:
  • Imino acids
  • Single letter amino acid code
  • Three letter amino acid code
  • Non-essential amino acids
  • Essential amino acids
  • Amino acids

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