Fructose, fructose 1-phosphate, and glyceraldehyde breakdown in carbohydrate metabolism.
Recent investigations showed that all enzymes that are involved in the catabolism of fructose via fructose 1-phosphate (F-1-p) are present in the bovine lens. The present studies were performed to provide information regarding the extent to which fructose, F-1-p and glyceraldehyde (GA) are actually catabolized via this pathway, and how they increase the lactate, alpha-glycerophosphate and glycerol concentrations. Incubation was performed with a homogenate of bovine lens equator. F-1-p, and particularly fructose + ATP, considerably increased lactate and alpha-glycerophosphate concentrations, while the glycerol concentration remained unchanged compared to controls. Lactate formation through GA was not observed; while small amounts of glycerol and alpha-glycerophosphate are formed, it seems that the major part is transformed to glycerate. The results show that the further breakdown of lenticular fructose occurs via F-1-p and that the phosphorylated C3 fragments (dihydroxyacetone phosphate) are transferred to the energy metabolism, which is not the case with GA.
D000818:Animals; D002417:Cattle; D004734:Energy Metabolism; D005632:Fructose / Q000378:metabolism*; D005636:Fructosephosphates / Q000378:metabolism*; D005985:Glyceraldehyde / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism; D066298:In Vitro Techniques; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D007908:Lens, Crystalline / Q000378:metabolism*
D005636:Fructosephosphates; D005994:Glycerophosphates; D007773:Lactates; C032284:fructose-1-phosphate; D005632:Fructose; D019344:Lactic Acid; D005985:Glyceraldehyde; C029620:alpha-glycerophosphoric acid; D005990:Glycerol