PDK isoforms phosphorylate lipo-PDH

Stable Identifier
Reaction [transition]
Homo sapiens
PDK-catalyzed phosphorylation (inactivation) of PDC E1 alpha subunit, Inactivation of PDC by phosphorylation of PDC E1 alpha component
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The mitochondrial pyruvate dehydrogenase (PDH) complex (lipo-PDH) irreversibly decarboxylates pyruvate to acetyl CoA, thereby serving to oxidatively remove lactate, which is in equilibrium with pyruvate, and to link glycolysis in the cytosol to the tricarboxylic acid cycle in the mitochondria matrix. Pyruvate Dehydrogenase Kinase (PDK) in the mitochondrial matrix catalyzes the phosphorylation of serine residues of the E1 alpha subunit of the PDH complex, inactivating it. Pyruvate negatively regulates this reaction, and NADH and acetyl CoA positively regulate it (Bao et al. 2004). Four PDK isoforms have been identified and shown to catalyze the phosphorylation of E1 alpha in vitro (Gudi et al. 1995, Kolobova et al. 2001, Rowles et al. 1996). They differ in their expression patterns and quantitative responses to regulatory small molecules. All four isoforms catalyze the phosphorylation of serine residues 293 ("site 1") and 300 ("site 2"); PDK1 can also catalyse the phosphorylation of serine 232 ("site 3"). Phosphorylation of a single site in a single E1 alpha subunit is sufficient for enzyme inactivation (Bowker-Kinley et al. 1998, Gudi et al. 1995, Kolobova et al. 2001, Korotchkina and Patel, 2001).

Literature References
PubMed ID Title Journal Year
11485553 Regulation of pyruvate dehydrogenase activity through phosphorylation at multiple sites

Kolobova, E, Tuganova, A, Boulatnikov, I, Popov, KM

Biochem J 2001
11486000 Site specificity of four pyruvate dehydrogenase kinase isoenzymes toward the three phosphorylation sites of human pyruvate dehydrogenase

Korotchkina, LG, Patel, MS

J Biol Chem 2001
9405293 Evidence for existence of tissue-specific regulation of the mammalian pyruvate dehydrogenase complex

Bowker-Kinley, MM, Davis, WI, Wu, P, Harris, RA, Popov, KM

Biochem J 1998
8798399 Cloning and characterization of PDK4 on 7q21.3 encoding a fourth pyruvate dehydrogenase kinase isoenzyme in human

Rowles, J, Scherer, SW, Xi, T, Majer, M, Nickle, DC, Rommens, JM, Popov, KM, Harris, RA, Riebow, NL, Xia, J, Tsui, LC, Bogardus, C, Prochazka, M

J Biol Chem 1996
7499431 Diversity of the pyruvate dehydrogenase kinase gene family in humans

Gudi, R, Bowker-Kinley, MM, Kedishvili, NY, Zhao, Y, Popov, KM

J Biol Chem 1995
Participant Of
Catalyst Activity
Catalyst Activity
pyruvate dehydrogenase (acetyl-transferring) kinase activity of PDK isoforms [mitochondrial matrix]
Physical Entity
This event is regulated
Orthologous Events
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