what makes up a protein
Protein molecules are often very large and are made up of hundreds to thousands of amino acid units. The 20 amino acids are combined in different ways to make up the 100,000 or so different proteins in the human body. Some of these proteins are in solution in the blood and other fluids of the body, and some are in solid form as the framework of tissue, bone and hair. Shipman, et al. suggests that they make up about 75% of the dry weight of our bodies. Proteins can be characterized as extremely long-chain polyamides.