Proteins are large, complex molecules that play many important roles in the body. They are critical to most of the work done by cells and are required for the structure, function and regulation of the body’s tissues and organs. A protein is made up of one or more long, folded chains of amino acids (each called a polypeptide), whose sequences are determined by the DNA sequence of the protein-encoding gene.
Protein. Most familiar are proteins that make up structures, such as muscle and, very importantly, proteins that fold and form what are known as enzymes. These proteins help your body carry out all of the chemical reactions it needs to keep you alive.
Division of Genomics and Society