Fructokinases

Enzymes that catalyse the phosphorylation of fructose — most importantly fructokinase (EC 2.7.1.4), which converts fructose to fructose 1-phosphate in the liver as the first step of dietary fructose metabolism. They are central to understanding how the body handles fructose from sucrose, high-fructose syrups, fruits and honey. Deficiency of hepatic fructokinase causes essential fructosuria, a benign condition, whereas defects further along the pathway cause serious disease; food scientists encounter these enzymes in studies of sugar metabolism and fermentation. In food fermentation, microbial fructokinases channel fructose into glycolysis, influencing flavour and ethanol yields in wine and brewing. Excessive fructose intake overwhelms hepatic fructokinase capacity, a mechanism implicated in metabolic research on sugary diets and non-alcoholic fatty liver disease.