You are made out of hundreds of specific proteins. Proteins also control how your body works. Every chemical reaction that happens in you body, from the ability of your blood to carry oxygen to the impulses of nerves, is controlled by proteins called enzymes. A protein is actually a polymer type of a molecule built of a sequence of amino acids. The following is a protein typical of what you have the ability to produce.
Yellow connections indicate intrachain disulfide linkages.
As you can see, ribonuclease contains 124 amino acids. Its particular structure can make it do things that no other enzyme can do. The following is one half of the hemoglobin molecule. Hemoglobin transports oxygen around your body and consists of two alpha and two beta chains of amino acids. One molecule has 574 amino acids.