Glucokinase/GCK: Proteins and Enzymes

Hexokinases phosphorylate hexose to form hexose 6-phosphate, the first step for hexose metabolism. There are four mammalian hexokinases (I, II, III and IV) and hexokinase IV is commonly known as glucokinase (GCK). Unlike hexokinase I, II and III, which have high affinity for glucose and are strongly inhibited by the product, glucose-6-phosphate, GCK has much lower affinity for glucose and is not inhibited by the product. Consequently, GCK has a Km for glucose of approximately 7 mM, which is 100 ...