Human Biochemistry, Volume 1 - Murray R. 1993

Bioenergetics and Metabolism of Carbohydrates and Lipids
Gluconeogenesis and the Pentose Phosphate Pathway
Pentose Phosphate Pathway or Hexose Monophosphate Shunt — Clinical Aspects

The Pentose Phosphate Pathway in erythrocytes supplies NADPH for the reduction of oxidized Glutathione (G—S—S—G) to reduced glutathione (2G—SH), a reaction catalyzed by glutathione reductase. Reduced glutathione destroys Н₂О₂ in erythrocytes in a reaction catalyzed by glutathione peroxidase:

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This reaction is of vital importance because the accumulation of Н₂О₂ can shorten the lifespan of erythrocytes (by increasing The rate of Hemoglobin oxidation to methemoglobin). It has been shown that there is an inverse relationship between glucose-6-phosphate dehydrogenase activity and erythrocyte resistance. In certain populations, a mutation has been identified that causes a deficiency of this enzyme; the consequence of this mutation is impaired NADPH production, which leads to erythrocyte hemolysis after patients take drugs that act as oxidants, such as the antimalarial drug primaquine, aspirin, and sulfonamides. The same consequences are triggered in some individuals by the consumption of fava beans (Vicia faba).

Determining transketolase activity in the Blood makes it possible to assess the degree of thiamine deficiency. The only condition in which an increase in its activity is observed is pernicious anemia.

References

Krebs H. A. Gluconeogenesis, Proc. R. Soc. Lond. [Biol.], 1964, 159, 545.

Landau B. R., Wood H. G. The pentose cycle in animal Tissues: Evidence for the classical and against the «L-type« pathway, Trends Biochem. Sсi., 1983, 8, 292.

Williams J. F. A critical examination of the Evidence of the Reactions of the pentose pathway in animal tissues, Trends Biochem. Sсi., 1980, 5, 315.

Wood T. The Pentose Pathway, Academic-Press, 1985.