Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.2 (PDK1)
 2,238 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presentation and treatment of a central hypoventilation syndrome in a boy with pyruvate dehydrogenase complex (PDHC) deficiency are reported. Dephosphorylated PDHC was assayed in disrupted fibroblasts after pretreatment with dichloroacetate, a pyruvate dehydrogenase kinase inhibitor. Maximal specific activity of activated patient PDHC was 10% to 30% of control values. Patient PDHC activity was not increased by alterations in concentrations of pyruvate or cofactors (thiamine pyrophosphate [TPP], coenzyme A [CoA], oxidized form of nicotinamide adenine dinucleotide [NAD+]). Clinically, normalization of plasma lactate by a high-lipid diet did not prevent slowly progressive neurologic decline. The patient manifested intermittent ataxia, episodic profound weakness, moderate psychomotor retardation, ophthalmoplegia, and retinal pigment epithelial changes. A true central hypoventilation syndrome was documented on the basis of rigorous radiologic, electrophysiologic, and pulmonary function criteria. Theophylline, progesterone, and ritalin neither altered ventilatory response to CO2 nor permitted weaning from the ventilator. In contrast, peripheral chemoreceptor stimulants (intravenous doxapram; oral almitrine) effected an acute doubling of minute ventilation with appropriate decreases in PaCO2. However, a positive response to long-term therapy with almitrine could not be unequivocally shown. It was concluded that measurement of disrupted fibroblast PDHC following dichloroacetate activation constitutes an accurate assay for PDHC deficiency. PDHC deficiency must be considered in the differential diagnosis of the central hypoventilation syndrome; this appears to be the first report of such an association. Finally, a therapeutic trial of a peripheral chemoreceptor agonist is warranted in the management of central hypoventilation syndrome.
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PMID:Central hypoventilation syndrome in pyruvate dehydrogenase complex deficiency. 643 1

Altered pyruvate dehydrogenase (PDH) functioning occurs in primary PDH deficiencies and in diabetes, starvation, sepsis, and possibly Alzheimer's disease. Currently, the activity of the enzyme complex is difficult to measure in a rapid high-throughput format. Here we describe the use of a monoclonal antibody raised against the E2 subunit to immunocapture the intact PDH complex still active when bound to 96-well plates. Enzyme turnover was measured by following NADH production spectrophotometrically or by a fluorescence assay on mitochondrial protein preparations in the range of 0.4 to 5.0 micro g per well. Activity is sensitive to known PDH inhibitors and remains regulated by phosphorylation and dephosphorylation after immunopurification because of the presence of bound PDH kinase(s) and phosphatase(s). It is shown that the immunocapture assay can be used to detect PDH deficiency in cell extracts of cultured fibroblasts from patients, making it useful in patient screens, as well as in the high-throughput format for discovery of new modulators of PDH functioning.
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PMID:Immunocapture and microplate-based activity measurement of mammalian pyruvate dehydrogenase complex. 1263 10

Phenyl butyrate (PB) has been proved to decrease pyruvate dehydrogenase (PDH) phosphorylation level and increase PDH activity by inhibiting pyruvate dehydrogenase kinase 1 (PDK1) in fibroblast cells, PDH deficiency zebrafish and wild type mice. PB has also shown efficacy in many cancers and so far, all of its anti-tumor activity has been attributed to the histone deacetylase (HDAC) inhibition. As PDK1/PDH controls the critical switch between oxidative phosphorylation and glycolysis in cancer cells, PDK1 is a key target in tumor metabolism for anti-cancer treatment. We hypothesize that the therapeutic effects of PB in cancers might also depend on suppressing PDK1 and promoting PDH activity, in addition to its proposed role as HDAC inhibitor. We showed that PB directly inhibited the kinase activity of PDK1 and increased the activity of PDH in an enzyme assay. In several different cancer cell lines, PB reduced the phosphorylation level of PDH, increased the mitochondrial respiration, decreased glycolysis in cytoplasm, reversed mitochondrial hyperpolarization, activated several proteins in apoptotic signaling pathway and then induced the apoptosis of cells. In summary, this is the first study indicated that PB could exert its anti-cancer effects through inhibiting PDK1, altering the mitochondrial bioenergetics and inducing apoptosis.
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PMID:Phenyl butyrate inhibits pyruvate dehydrogenase kinase 1 and contributes to its anti-cancer effect. 2845 Jan 54