Glycerol phosphate shuttle

Glycerol phosphate shuttle

The glycerol-3-phosphate shuttle is a mechanism that regenerates NAD+ from NADH, a by-product of glycolysis. Its importance in transporting reducing equivalents is secondary to the malate-aspartate shuttle.


In this shuttle, the enzyme called cytoplasmic glycerol-3-phosphate dehydrogenase 1 (GPDH-C) converts dihydroxyacetone phosphate (2) to glycerol 3-phosphate (1) by oxidizing one molecule of NADH to NAD+ as in the following reaction:[1]

Reverse path

Glycerol-3-phosphate gets converted back to dihydroxyacetone phosphate by a membrane-bound mitochondrial glycerol-3-phosphate dehydrogenase 2 (GPDH-M), this time reducing one molecule of enzyme-bound flavin adenine dinucleotide (FAD) to FADH2. FADH2 then reduces coenzyme Q (ubiquinone to ubiquinol) which enters into oxidative phosphorylation.[1] This reaction is irreversible.[2]


The glycerol-3-phosphate shuttle allows the NADH synthesized in the cytosol by glycolysis to contribute to the oxidative phosphorylation pathway in the mitochondria to generate ATP.[1] It has been found in animals, fungi, and plants.[2]

See also


External links

  • (describes the shuttle in the context of glycolysis)