Pentose Phosphate Pathway

Generates NADPH and ribose-5-phosphate for biosynthesis.

Overview

The pentose phosphate pathway (PPP) branches from glycolysis at glucose-6-phosphate and consists of two phases: the oxidative phase, which generates NADPH, and the non-oxidative phase, which produces ribose-5-phosphate for nucleotide synthesis. NADPH serves as a reducing agent in fatty acid synthesis, cholesterol synthesis, and protection against oxidative stress via the glutathione system.

Cellular Location

Cytoplasm

Clinical Significance

Essential for NADPH production and nucleotide biosynthesis; G6PD deficiency is the most common enzyme deficiency worldwide.

Key Molecules

Glucose-6-phosphate 6-Phosphogluconate Ribulose-5-phosphate Ribose-5-phosphate NADPH Erythrose-4-phosphate

Key Enzymes

Glucose-6-phosphate dehydrogenase (G6PD)6-Phosphogluconate dehydrogenase Transketolase Transaldolase

Related Pathways

Glycolysis

The breakdown of glucose into pyruvate, yielding ATP and NADH.

Nucleotide Biosynthesis

De novo and salvage pathways for purine and pyrimidine nucleotide production.