Inactivation of PDC by phosphorylation of PDC E1 alpha component Authored: Gopinathrao, G, 2007-11-26 20:29:38 EC Number: 2.7.11.2 PDK-catalyzed phosphorylation (inactivation) of PDC E1 alpha subunit Pubmed11485553 Pubmed11486000 Pubmed15491150 Pubmed7499431 Pubmed8798399 Pubmed9405293 Pyruvate Dehydrogenase Kinase (PDK) in the mitochondrial matrix catalyzes the phosphorylation of serine residues of the E1 alpha subunit of the pyruvate dehydrogenase 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 also catalyzes 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). Reactome Database ID Release 43203946 Reactome, http://www.reactome.org ReactomeREACT_12462 Reviewed: D'Eustachio, P, 2008-01-11 20:49:08 has a Stoichiometric coefficient of 2 pyruvate dehydrogenase complex phosphorylated pyruvate dehydrogenase complex