Fruktokinase

Fruktokinase is an enzyme that catalyzes the phosphorylation of fructose. Specifically, it adds a phosphate group to fructose, a simple sugar. This reaction is the first step in the metabolism of fructose in many organisms, including humans. There are several types of fructokinase, with different substrate specificities and cellular locations. In humans, the most well-known is fructokinase (also known as ketohexokinase), found primarily in the liver. This enzyme phosphorylates fructose to fructose-1-phosphate. Another important fructokinase is hexokinase, which can phosphorylate fructose as well as glucose and other hexoses, typically to glucose-6-phosphate. The activity of fructokinase is regulated by the availability of its substrates, fructose and ATP. High levels of fructose can lead to increased fructokinase activity. The product, fructose-1-phosphate, is then further metabolized through the glycolytic pathway. Defects in fructokinase activity can lead to genetic disorders. For example, hereditary fructose intolerance is caused by a deficiency in aldolase B, an enzyme downstream of fructokinase, but fructokinase itself can be affected in certain rare conditions. Understanding fructokinase is crucial for comprehending fructose metabolism and its implications in health and disease.