Summary The Pentose Phosphate Pathway

BCM 252 – Study Unit 3
Pentose Phosphate Pathway


The Pentose Phosphate Pathway

• Pentose phosphate pathway (phosphogluconate pathway, hexose
monophosphate pathway) – oxidative phase 1: the pathway oxidizes glucose 6-
phosphate, producing pentose phosphates and NADPH
• Nonoxidative (phase 2 – reversible) – recycles pentose phosphates back to
glucose 6-phosphate
• Allows for ingested and synthesized ribose sugars to enter the glycolytic pathway

, Cells and Tissues that use the pentose phosphate pathway

• Rapidly dividing cells use ribose 5-phosphate to make RNA, DNA, and
coenzymes
• Tissues that carry out extensive fatty acid synthesis – the liver, adipose tissue,
and lactating mammary gland) require the NADPH provided by this pathway
• Tissues that actively synthesize cholesterol and steroid hormones – the liver,
adrenal glands, and gonads) require the NADPH provided by this pathway


Oxidative phase generates NADPH

• Pathways require NADPH
1. Synthesis:
➢ Fatty acid biosynthesis
➢ Cholesterol biosynthesis
➢ Neurotransmitter biosynthesis
➢ Nucleotide biosynthesis
2. Detoxification:
➢ Reduction of oxidized glutathione
➢ Cytochrome P450 monooxygenases


Glucose-6-Phosphate Dehydrogenase Deficiency

• It can be fatal in cases of high oxidative stress
➢ Certain drugs, herbicides, and some foods
• Resistance to malaria due to high oxidative stress in red blood cells
• Reduced GSH protects cells against radicals