Poly amino acids are polyamides composed of single amino
acid, and differ from proteins in various aspects. While the protein
is composed of a variety of amino acids, the poly amino acid is
composed of only one type of amino acid (at least in the backbone).
DNA directs the placement of the amino acids in a specific sequence
to form a molecule of protein. Poly amino acids, on the
other hand, are biosynthesized by a different pathway in microorganisms
(Kunioka, 1997). Amide linkages in proteins are only
formed between a-amino and a-carboxylic groups (a-amide linkages),
whereas amide bonds in poly amino acids involve other side
chain functions (i.e. b- and c-carboxylic and e-amino groups)