Amino acid Any of a class of 20 molecules that are combined to form proteins in living things. The sequence of amino acids in a protein and hence protein function are determined by the genetic code.
Amino acids contain a basic amino (NH2) group, an acidic carboxyl (COOH) group and a side chain (R - of a number of different kinds) attached to an alpha carbon atom.

Thus the general formula is:
basic aminoacid structure