Hepatic fructokinaseHepatic fructokinase is an enzyme that catalyzes the phosphorylation of fructose to produce fructose-1-phosphate.IsoformsIn humans, ketohexokinase is encoded by the KHK gene, which produces two isoforms, KHK-A and KHK-C, through alternative splicing.KHK-C is primarily expressed in the liver, kidney, and intestine. It has a high affinity for fructose and is responsible for the majority of fructose metabolism.KHK-A is ubiquitously expressed in many tissues at low levels. It has a significantly lower affinity for fructose compared to the C isoform.