What's inside an enzymes
Like all other proteins, enzymes are made of amino acids. Each enzyme is made up of between a hundred and up to a million amino acids placed like pearls on a string. Each amino acid is bonded to the next by chemical bonds. Each enzyme has its own unique sequence of amino acids, which is determined by the genes in the cells. The vast majority of enzymes are made of only 20 different kinds of amino acid. The structure and function of the enzyme is determined by the order of the amino acids.
In most enzymes, the string of amino acids is coiled and folded thousands of times to form a highly complex three-dimensional structure, which is unique to each enzyme. It is the chemical interactions between the amino acids that force the enzymes into their three-dimensional structure, which is held together by the many different links between the different amino acids.
The unique three-dimensional structure of each enzyme determines the function of the enzyme. Even slight changes in the sequence of the amino acids on the string have a huge impact on the structure and function of the protein. With just one, or perhaps a few, amino acids replaced or switched, an enzyme may not only look different, but also act differently and convert to working on other biological molecules or treating them differently.
Although enzymes are large molecules with hundreds of amino acids, only a small part of the enzyme participates in the catalysis of biochemical reactions. This is called the active site. The three-dimensional structure of the enzyme determines the appearance of the active site. The active site precisely accommodates the shape of the biological substrate (material on which it acts). The enzyme and substrate fit together like a key in a lock, and only substrates with the right shape will be transformed by the enzyme. This is what makes enzymes specific in their action.