Fructose metabolism

Plasma fructose may enter cells for glycolysis or gluconeogenesis by one of two pathways:

• in hepatocytes:
  • fructokinase converts fructose to fructose-1-phosphate
  • fructose-1-phosphate aldolase converts fructose-1-phosphate to dihydroacetone phosphate and glyceraldehyde
  • triose kinase converts glyceraldehyde to glyceraldehyde-3-phosphate
  • triose phosphate isomerase converts dihydroacetone phosphate to glyceraldehyde-3-phosphate
  • glyceraldehyde-3-phosphate then enters further glycolytic or gluconeogenic reactions according to the energy status of the hepatocyte
    
    
• in other cells, particularly adipocytes:
  • hexokinase converts fructose into fructose-6-phosphate; fructose competes with glucose for phosphorylation
  • fructose-6-phosphate enters glycolysis