Amino acids are the building blocks of proteins and are mainly used to build up body tissue. Essential variants of this cannot be produced by an organism itself, they must therefore be ingested with food. Amino acids are found in all living beings. These include organic compounds which contain at least one amino group and one carboxyl group as functional groups, i.e. which have structural characteristics of the amines and carboxylic acids.
A. are linked together to form chains in which the carboxy group of one amino acid forms a peptide bond with the amino group of the next. The acids linked in this way to a polymer differ in their side chains and together determine the form with which the polypeptide then folds up to the native protein in an aqueous medium. Their base sequence specifies the amino acid sequence in certain sections, one base triplet representing a codon which can represent a specific amino acid. The A. encoded as building blocks for the formation of proteins are also called proteinogenic amino acids, in humans there are 21 different amino acids.
After translation, the side chains of some amino acids built into the protein can still be modified.