All enzymes are proteins. Enzymes are made up of long chains of proteins called amino acids. These chains are held together by peptide bonds to form a 3-dimensional type of structure. Some enzymes are composed of only one chain of amino acids while others are made up of several amino acid chains. No two different types of enzymes have the same amino acid structure. Each enzyme is made up of a unique chain of amino acids, which gives each enzyme its own unique shape.