Metabolism
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An adverse response to antimalarial medication - and a fatal reaction to fava beans
Key points from this exercise:
The tripeptide glutathione is an important part of antioxidant defences of the cell, and glutathione reductase requires NADPH to reduce GSSG back to GSH.
The only source of NADPH in red blood cells (and a major source in other tissues) is the first two reactions in the pentose phosphate pathway, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase.
The pentose phosphate pathway is especially important in tissues that synthesise fatty acids (liver, adipose tissue and lactating mammary gland) as the source of about half the NADPH required.
The pentose phosphate pathway provides an alternative to part of the pathway of glycolysis, and is important as the source of ribose.
Glucose 6-phosphate dehydrogenase deficiency is the commonest genetic disease in human beings; it is an X-linked recessive condition. It is likely that heterozygote carriers have resistance to malaria.