Pyruvate dehydrogenase (PDH)

The key regulatory site in cellular metabolism

PDH Application guide

View our optimal range to measure all aspects of the pyruvate dehydrogenase complex (PDH). PDH deficiencies, diabetes, starvation, sepsis, and possibly Alzheimer's disease have been linked to altered PDH functioning.

1. Structure and function
2. Related products
   • Monoclonal antibodies
   • Antibody cocktails
   • In-Cell ELISA kits
   • Proteins quantity assays
   • Enzyme activity assays
   • Multiplexing arrays
   • Immunocapture kits
   • Recombinant proteins
3. PDH Phosphorylation/Dephosphorylation protocols & references

1. Structure and function

PDH is at the centre of aerobic carbohydrate metabolism. It is localized in the matrix space of mitochondria where it catalyzes the irreversible oxidative decarboxylation of pyruvate entering the organelle to produce acetyl-CoA, NADH and CO2. Thus it links and regulates the flow of energy in cells by determining when pyruvate should be used for oxidative phosphorylation versus "neutralized" to lactic acid to allow continued glycolysis. At the same time the control of acetyl Co-A directly influences fatty acid oxidation and production of ketone bodies.

Figure 1. Five sequential reactions of PDH-catalyzed oxidative decarboxylation of pyruvate to Acetyl Coenzyme A.

PDH is a large complex (MW around 9 MDa) consisting of multiple copies of three enzymes: pyruvate dehydrogenase (E1), dihydrolipoamide transacetylase (E2) and dihydrolipoamide dehydrogenase (E3). The E1 enzyme is a tetramer comprised of two alpha and two beta subunits and is present in 30 copies. In the mammalian enzyme, 60 copies of E2 forms the core with the other subunits organized regularly around its periphery. Intermediates of one enzyme are passed to become substrate for the next in a reaction sequence that is a prototype substrate channeling mechanism. In addition, one structural subunit, the E3 binding protein, has been identified to protein support the interactions between the E2 and E3 subunits.

The activity of PDH is regulated by reversible phosphorylation of three serine residues on the E1alpha subunit. The phosphorylation of these sites is catalyzed by PDH kinases (PDK). There are four known isoforms of PDKs that are distributed differently in tissues. Their expressions are regulated differently by factors such as starvation, hypoxia and utilization of glucose and fatty acids in various tissues. In addition, transcription regulators such as PGC-1 alpha, retinoic acid and the glucocorticoid receptor are involved.

Dephosporylation to restore the activity of PDH is catalyzed by PDH phosphatases (PDP). There are two known isoforms of PDPs, which are expressed differently in various tissues; PDP1 is present in high levels in skeletal muscle and PDP2 in liver and adipocytes.

Figure 2. A schematic of the reactions controlling pyruvate dehydrogenase.

Each of the PDK’s and PDP’s is under transcriptional control in response to different cellular stress events.

2. Related products

Mouse monoclonal antibodies

Antibody cocktails

In-Cell ELISA kits

Protein quantity assays

Enzyme activity assays

ELISA Kits

Multiplex arrays

Immunocapture kits

Recombinant proteins

PDH Kinases (PDKs) deactivate PDH by reversible phosphorylation. In humans and rodents, 4 PDK's are present in an organ-dependent manner. In all cases, PDK's are physically part of the PDH complex (binding via lipoyl domain 2 of E2), and they phosphorylate the E1 subunit at 3 specific serine residues. PDH phosphatases remove the phosphorylation and restore activity of PDH.

3. PDH Phosphorylation/Dephosphorylation protocols & references

Download the following PDH protocols.

• Measurement of Endogenous PDH Activity Relative to the Fully-Phosphorylated and Dephosphorylated States
• Measurement of Endogenous PDH-E1-α Phospho-Serine293 Levels Relative to the Fully-Phosphorylated and Dephosphorylated States
• PDH Kinase Inhibitor Screening Assay Based on PDH Activity
• PDH Kinase Inhibitor Screening Assay Based on Quantitation of Phosphoserines 232, 293 or 300

References on the Structure, Function and Regulation of PDH.

• Sugden MC, Bulmer K, & Holness MJ. (2001) “Fuel Sensing Mechanisms Integrating Lipid and Carbohydrate Utilization.” Biochem Soc Trans. 29, 272-278. PMID 11356166
• Patel MS & Korotchkina LG. (2006) “Regulation of the Pyruvate Dehydrogenase Complex.” Biochem Soc Trans. 34, 217-222. PMID 16545080
Utilization.” Biochem Soc Trans. 29, 272-278. PMID 11356166
• Roche TE & Hiromasa Y. (2007) “Pyruvate dehydrogenase kinase regulatory mechanisms and inhibition in diabetes, heart disease and cancer.” Cell Mol Life. 64, 830-849. PMID 17310282
• Degenhardt T, et al. (2007) “Three members of the human pyruvate dehydrogenase kinase gene family are direct targets of peroxisome proliferator - activator receptor ß/delta. JJ Mol Biol. 372, 341-355. PMID 17669420



Back to homepage