Hexokinase-3, also known as Hexokinase type III, HKIII and HK3, is a protein which belongs to thehexokinase family. Hexokinase-3 / HK3 is anenzymewhich in humans is encoded by theHK2gene. Hexokinases phosphorylate glucoseto produceglucose 6-phosphate, committing glucose to theglycolytic pathway. In mammalian tissues hexokinase exists as four isoenzymes encoded by distinct genes. These proteins are homologous and are organized in two homologous domains, with the exception of hexokinase type IV which has only one. This organization is believed to be the result of a duplication and tandem fusion event involving the gene encoding for the ancestral hexokinase. The gene encodes hexokinase-3. Similar to hexokinases-1 and hexokinases-2, thisallostericenzyme is inhibited by its product glucose 6-phosphate.