Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purified aurochs heart pyruvate dehydrogenase complex (PDC) saturated to approximation 60% with endogenous thiamine pyrophosphate (TPP), was slowly and incompletely inactivated by its kinase in the presence of ATP. Exogenous TPP or ADP, but not pyruvate, strongly inhibited the kinase activity. The kinetic properties of the aurochs heart PDC kinase suggested the occurrence of two active sites each with different affinities for ATP (K'm - 1.7 microM, K''m = 48 microM).
Biochem Mol Biol Int 1995 Oct
PMID:An investigation of the kinase activity of aurochs heart pyruvate dehydrogenase complex. 867 14

The pyruvate dehydrogenase complex (PDC) has been purified to apparent homogeneity from the insect trypanosomatid, Crithidia fasciculata, a member of the most primitive eukaryotic group to contain mitochondria. Separation of the purified PDC by SDS-PAGE yielded five bands of 70 (p70), 60 (p60), 55, 46 and 36.5 kDa, which appeared to correspond to dihydrolipoyl dehydrogenase binding protein (E3BP), dihydrolipoyl transacetylase (E2), E3, E1 alpha and E1 beta, respectively. The purified complex did not exhibit endogenous PDHa kinase activity. p70 was much less abundant than p60. Polyclonal antisera raised against p70 did not cross-react with p60, and antisera raised against p60 did not cross-react with p70, suggesting that p60 did not arise from p70 by proteolysis. Both p70 and p60 contained similar amino terminal sequences. Both sequences contained the MPALSP motif similar to sequences present in both E3BP and E2 from other sources. Incubation of the purified PDC with [2-14C]pyruvate in the absence of CoA resulted in the acetylation of both p70 and p60, suggesting that both proteins contained lipoyl domains, but the specific incorporation of label into p70 was significantly greater than for p60. Limited proteolysis of the acetylated complex with trypsin yielded two major fragments derived from p60 of 35 and 30 kDa, corresponding to E2L and E2I, and one major acetylated fragment of 58 kDa derived from p70. Therefore, these results suggest that p70 is an E3BP and given its apparent M(r) and degree of acetylation, it contains multiple lipoyl domains.
Mol Biochem Parasitol 1995 Dec
PMID:Pyruvate dehydrogenase complex from the primitive insect trypanosomatid, Crithidia fasciculata: dihydrolipoyl dehydrogenase-binding protein has multiple lipoyl domains. 872 Jan 78

Ranolazine has shown anti-anginal efficacy in humans and cardiac anti-ischaemic activity in models, but without affecting haemodynamics or baseline contraction. In isolated normoxic rat hearts, Langendorff-perfused for 30 min with 11 mM glucose, 3% albumin, and 0.4 mM or 0.8 mM palmitate, 20 microM ranolazine significantly increased active, dephosphorylated, pyruvate dehydrogenase (PDHa), but not with no palmitate or 1.2 mM palmitate. Dichloroactetate (DCA, 1 mM), a PDHa kinase inhibitor, significantly increased PDHa in hearts perfused with 0, 0.4 or 0.8 mM but not 1.2 mM palmitate. PDHa was significantly increased with 1.2 mM palmitate by DCA plus ranolazine, and additive effects were also seen at 0.8 mM palmitate. Activation of PDH by ranolazine and promotion of glucose oxidation offers a plausible means by which the drug may be anti-ischaemic nonhaemodynamically. Extensive studies with extracted enzymes and isolated rat heart mitochondria failed to demonstrate any effects of ranolazine on PDH kinase or phosphatase, or on PDH catalytic activity, whereas effects of other known effectors (such as DCA) were readily demonstrable, suggesting that ranolazine activates PDH indirectly. Further analyses of the hearts revealed that ranolazine reduced acetyl CoA content under all conditions where fatty acid was present, and +/- DCA which itself had little effect. In the absence of fatty acid, ranolazine and/or DCA raised acetyl CoA. In perfusions where octanoate (+/- albumin) replaced palmitate, ranolazine still decreased acetyl CoA, but not when acetate replaced palmitate. In octanoate-perfused hearts, the contents of the C4, C6 and C8 CoA esters were all increased by ranolazine. This is consistent with ranolazine causing an inhibition of fatty acid beta-oxidation leading to decreased acetyl CoA and activation of PDH.
J Mol Cell Cardiol 1996 Feb
PMID:Ranolazine increases active pyruvate dehydrogenase in perfused normoxic rat hearts: evidence for an indirect mechanism. 872 66

The phylogeny and substitution rates of the mammalian X chromosome-located and autosomal phosphoglycerate kinase and pyruvate dehydrogenase genes were investigated. Compatibility analysis was used to show reticulate evolution in these genes. Analysis of the marsupial, mouse, and human phosphoglycerate kinase genes suggests that at least two recombination events have taken place, one occurring about the time of the placental-marsupial split involving exons 1-5 and the other before the primate-rodent split involving exons 9-10. Similar analysis of the pyruvate dehydrogenase genes indicates a recombination event involving exons 2-3 at a time before the primate-rodent split and a gene conversion between exons 3-4 in the human somatic and testis-specific pyruvate dehydrogenase genes after the primate-rodent split. This demonstrates that genetic exchange can occur between paralogous genes at widely separated chromosomal locations. Estimation of nucleotide substitution rates in these genes confirmed a higher substitution rate in the pyruvate dehydrogenase genes. In the phosphoglycerate kinase genes, there is no difference between the substitution rates in mice and humans and between the X chromosome- and autosome-located genes. A greater substitution rate was noted in the mouse autosomal pyruvate dehydrogenase gene when compared with the other mouse and human genes. This may be a result of either directional natural selection or a relaxation of functional constraint at this specific gene.
Mol Biol Evol 1996 Sep
PMID:Evolution of mammalian X-linked and autosomal Pgk and Pdh E1 alpha subunit genes. 875 9

Oligonucleotide-directed site-specific mutagenesis was carried out on pyruvate decarboxylase (EC 4.1.1.1) from Saccharomyces cerevisiae at three of the four cysteines (152, 221, and 222), the fourth (69) being buried according to X-ray crystallographic results [Arjunan et al. (1996) J. Mol. Biol. 256, 590-600]. All of the variants still retained significant activity, and all could be purified to homogeneity. FT-IR experiments were run on the C221S, C222S, C221S/C222S and C152A variants, as well as on the wild-type enzyme. There is a band present at 2557 cm-1 in the spectra of all variants and the wild-type enzyme, except in the spectrum of the C152A variant. This frequency is appropriate to a cysteine S-H stretching mode. It was therefore concluded that C152 is the only undissociated cysteine on the enzyme at pH 6.0, the pH optimum of this enzyme, whereas C221, C222, and C69 are all ionized. Isoelectric focusing experiments were carried out on all of these variants, as well as on the H92A variant (H92 is across the domain divide on the alpha domain, from C221 located on the beta domain). The variation in isoelectric points deduced from the data was consistent with removal of negative charges concomitant with the C221S, C222S, and C221S/C222S substitutions and removal of a positive charge with the H92A substitution when compared to that of the wild-type enzyme. The results of these two types of experiments are in good accord and suggest that the site of substrate activation at C221 [Baburina et al. (1994) Biochemistry 33, 5630-5635] is comprised of a Cys221S- +HHis92 ion pair, not unlike that found in papain and glyceraldehyde-3-phosphate dehydrogenase. This finding suggests that the regulatory site of this enzyme has been optimized for nucleophilic reactivity between the thiolate of C221 and the keto carbon of the 2-oxoacid.
 ...
PMID:Three of four cysteines, including that responsible for substrate activation, are ionized at pH 6.0 in yeast pyruvate decarboxylase: evidence from Fourier transform infrared and isoelectric focusing studies. 875 79

The purposes of this study were to: (1) assess myocardial pyruvate dehydrogenase (PDH) activity and substrate exchange under well-perfused and ischemic conditions; (2) determine the metabolic effects of an intra-coronary infusion of the PDH activator, dichloroacetate (DCA); and (3) measure the effects of ischemia and DCA on malonyl CoA levels. Experiments were performed in anesthetised open-chest swine under non-ischemic conditions, followed by 40 min with a 60% reduction in left anterior descending coronary artery (LAD) blood flow. Myocardial needle biopsies for measurement of PDH activity were taken after an intracoronary infusion of either saline or DCA (1 mM in LAD blood) under aerobic conditions, and after 37 min of ischemia. Pyruvate dehydrogenase activity was measured with and without maximal activation by swine PDH phosphatase. Malonyl CoA and acetyl CoA were measured after 40 min of LAD ischemia in myocardium from the ischemic DCA- or saline-treated LAD bed, and the non-ischemic untreated left circumflex coronary artery (CFX) perfusion bed. Net glucose, lactate and free fatty acid (FFA) uptakes were measured across the LAD perfusion bed throughout the study. Dichloroacetate treatment increased the amount of active dephosphorylated PDH to 88% of the total activity under aerobic conditions, compared to 55% with saline (P < 0.01). Ischemia did not significantly change PDH activation state in either group. Acetyl CoA and malonyl CoA contents were significantly elevated in ischemic DCA-treated myocardium compared to saline-treated ischemic myocardium. Dichloroacetate treatment significantly lowered rates of myocardial FFA uptake under both aerobic and ischemic conditions, but did not effect glucose uptake or lactate exchange. Free fatty acid uptake was negatively correlated to malonyl CoA levels (r = -0.68) during ischemia. It is proposed that the inhibition of FFA uptake observed with DCA in ischemic myocardium is due to malonyl CoA inhibition of carnitine palmitoyl transferase I.
J Mol Cell Cardiol 1996 May
PMID:Pyruvate dehydrogenase activity and malonyl CoA levels in normal and ischemic swine myocardium: effects of dichloroacetate. 876 30

A two-year randomized, double-blind, placebo-controlled clinical trial used paired serum samples from 122 patients with primary biliary cirrhosis to compare the effect of ursodeoxycholic acid and colchicine on their immune parameters. IgG antibodies to pyruvate dehydrogenase, the major autoantigen in primary biliary cirrhosis, were determined by enzyme-linked immunosorbent assay and immunoblot; enzyme inhibition assay against pyruvate dehydrogenase was used to test the changes of the functional reactivity of the serum autoantibodies. Treatment with ursodeoxycholic acid decreased both the level of IgG antibodies to pyruvate dehydrogenase (P < 0.01) and the inihibitory titer of the sera for pyruvate dehydrogenase (P < 0.01). Treatment with colchicine or placebo showed no statistically significant changes in either the antibody levels or the inhibitory titers. Ursodeoxycholic acid thus alters the immune parameters of patients with primary biliary cirrhosis. The mechanism of these changes needs further investigation.
J Mol Med (Berl) 1996 May
PMID:Ursodeoxycholic acid treatment lowers the serum level of antibodies against pyruvate dehydrogenase and influences their inhibitory capacity for the enzyme complex in patients with primary biliary cirrhosis. 877 63

The three-dimensional solution structure of the lipoyl domain of the 2-oxoglutarate dehydrogenase complex from Azotobacter vinelandii has been determined from nuclear magnetic resonance data by using distance geometry and dynamical simulated annealing refinement. The structure determination is based on a total of 580 experimentally derived distance constraints and 65 dihedral angle constraints. The solution structure is represented by an ensemble of 25 structures with an average root-mean-square deviation between the individual structures of the ensemble and the mean coordinates of 0.71 A for backbone atoms and 1.08 A for all heavy atoms. The overall fold of the lipoyl domain is that of a beta-barrel-sandwich hybrid. It consists of two almost parallel four-stranded anti-parallel beta-sheets formed around a well-defined hydrophobic core, with a central position of the single tryptophan 21. The lipoylation site, lysine 42, is found in a beta-turn at the far end of one of the sheets, and is close in space to a solvent-exposed loop comprising residues 7 to 15. The lipoyl domain displays a remarkable internal symmetry that projects one beta-sheet onto the other beta-sheet after rotation of approximately 180 degrees about a 2-fold rotational symmetry axis. There is close structural similarity between the structure of this 2-oxoglutarate dehydrogenase complex lipoyl domain and the structures of the lipoyl domains of pyruvate dehydrogenase complexes from Bacillus stearothermophilus and Escherichia coli, and conformational differences occur primarily in a solvent-exposed loop close in space to the lipoylation site. The lipoyl domain structure is discussed in relation to the process of molecular recognition of lipoyl domains by their parent 2-oxo acid dehydrogenase.
J Mol Biol 1996 Aug 23
PMID:Solution structure of the lipoyl domain of the 2-oxoglutarate dehydrogenase complex from Azotobacter vinelandii. 878 Jul 84

The RAG3 gene has been cloned from a Kluyveromyces lactis genomic library by complementation of the rag3 mutation, which shows impaired fermentative growth on glucose in the presence of respiratory inhibitors. From the nucleotide sequence of the cloned DNA, which contained an open reading frame of 765 codons, the predicted protein is 49.5% identical to the Pdc2 protein of Saccharomyces cerevisiae, a regulator of pyruvate decarboxylase in this yeast. Measurement of the pyruvate decarboxylase activity in the original rag3-1 mutant and in the null mutant confirmed that the RAG3 gene is involved in pyruvate decarboxylase synthesis in K. lactis. The effect is exerted at the mRNA level of the pyruvate decarboxylase structural gene KIPDCA. Despite analogies between the RAG3 gene of K. lactis and the PDC2 gene of S. cerevisiae, these genes were unable to reciprocally complement.
Mol Microbiol 1996 May
PMID:RAG3 gene and transcriptional regulation of the pyruvate decarboxylase gene in Kluyveromyces lactis. 879 73

The pdc1 gene encoding pyruvate decarboxylase has been isolated and sequenced from an IR54 rice genomic library. In contrast to a previously isolated intron-less rice genomic pdc, pRgpdc3, this gene contains five intervening introns in the coding region and corresponds to a cDNA clone, pRcpdc1, isolated from an IR54-cDNA library constructed from anaerobically-induced mRNAs. Comparison of the deduced amino acid sequence of this gene with that of the rice pdc2 and pdc3 showed 88% and 89% similarity, and 78% and 79% identity, respectively. Southern blots indicated that more than three genes constitute the pdc gene family in rice. pdc1 is highly inducible under anaerobic conditions. Rice pdc2 is also inducible by anoxia but to a much lesser extent than pdc1.
Plant Mol Biol 1996 Jul
PMID:Characterization of pyruvate decarboxylase genes from rice. 880 7


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>