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Petersen A , Kappler F , Szwergold BS , Brown TR
Fructose Metabolism in the Human Erythrocyte - Phosphorylation to Fructose 3-Phosphate
Biochemical Journal. 1992 Jun 1;284 :363-366
PMID: ISI:A1992HY20300011   
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Abstract
In human erythrocytes, the first step in the metabolism of fructose is generally thought to be phosphorylation to fructose 6-phosphate catalysed by hexokinase. In variance with this assumption, we show here that fructose in these cells is metabolized primarily to fructose 3-phosphate by a specific 3- phosphokinase. This process has an overall estimated K(m) of 30 mM with respect to extracellular fructose and an apparent V(max) of 0.6-mu-mol/h per ml. At a fixed concentration of fructose in the medium, the accumulation of fructose 3- phosphate was linearly dependent on the duration of incubation up to 5 h and was not affected by glucose. Once accumulated, fructose 3-phosphate appears to be degraded and/or relatively slowly metabolized, decreasing by only approximately 30% after a 12 h incubation in a fructose-free medium.
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English Article 2 HY203 BIOCHEM J