lysine

One of the essential amino acids, present in many common proteins. Its proportion in the proteins of some important food plants (including wheat and corn) is so small that populations dependent on these grains as the sole source of dietary protein suffer from lysine deficiency, affecting growth in children and general well-being in adults. It is used in biochemical and nutritional research, in pharmaceuticals, in fortified foods, and as a nutritional supplement and feed additive.