isocitrate dehydrogenase regulation

The Krebs’ cycle and the glyoxylate bypass. As summarized in Figure 5, our biochemical analysis suggested that IDH-r is a redox-sensitive protein and that the redox change affects IDH activity. These results imply that changes in the mitochondrial adenylate energy charge have no direct impact on IDH activity in Arabidopsis. ATP and NADH inhibit this enzyme, while ADP and calcium activate it. By using the recombinant subunits, we clearly showed that both IDH-r and IDH-c are essential for ensuring the catalytic activity of Arabidopsis IDH (Figure 1B). Isocitrate dehydrogenase (IDH) is an essential enzyme for cellular respiration in the tricarboxylic acid (TCA) cycle. Trends Plant Sci. The α-ketoglutarate is oxidized by reducing the NAD to NADH and releasing one molecule of CO2. For re-reduction (Ox → Red) treatment, IDH-r after Ox treatment was incubated in 50 mM DTT for 30 min. The regulatory mechanism of plant mitochondrial IDH thus remains poorly characterized. The reaction is stimulated by the simple mechanisms of substrate availability (isocitrate, NAD or NADP , Mg / Mn ), product inhibition by NADH (or NADPHoutside the citric acid cycle) and alpha-ketoglutarate, and competitive feedback inhi… Recurrent mutations in IDH1 or IDH2 are prevalent in several cancers including glioma, acute myeloid leukemia (AML), cholangiocarcinoma, and chondrosarcoma. Succinate Dehydrogenase 7.) These products are then used to drive electron transport in the respiratory chain and coupled ATP production. Although it has been recognized that the Trx-o resides in plant mitochondria (Laloi et al., 2001), information about the target proteins of Trx-o is limited to date. Bacterial IDHs are reversibly regulated by phosphorylation of a strictly conserved serine residue at the active site. Cytosolic NADP-dependent isocitrate dehydrogenase contributes to redox homeostasis and the regulation of pathogen responses in Arabidopsis leaves. Sci. Regulation of NAD- and NADP-dependent isocitrate dehydrogenases by reduction levels of pyridine nucleotides in mitochondria and cytosol of pea leaves. This form is considered to be common in plant IDH, but there has been only indirect supporting evidence to date in the form of growth restoration of yeast IDH mutants by complementation with plant IDH genes (Lancien et al., 1998; Lemaitre and Hodges, 2006). IDH-r was determined to be the target of oxidative modifications forming an oligomer via intermolecular disulfide bonds. See Materials and Methods for details. 276, 1204–1210. IDH is responsible for catalyzing the reversible conversion of isocitrate to alpha-ketoglutarate and CO 2 in a two-step reaction . Whole extracts were concentrated using a centrifugal concentrator and desalted using Solid Phase Extraction C-TIP (Nikkyo Technos). Further investigation is required for concluding this possibility. The E. coli enzyme exhib-its no allosteric regulation but is instead regulated by phospho-rylation. ATP inhibits Citrate Synthase. (C) The effect of adenylate on IDH activity under several concentrations of isocitrate. In the process, two hydrogens are also removed. Expression was induced by adding 0.5 mM IPTG, followed by further culture at 21°C overnight. Acad. doi: 10.1104/pp.109.138073, Millar, A. H., Whelan, J., Soole, K. L., and Day, D. A. Thioredoxin (Trx), a small ubiquitous protein, plays a crucial role in redox regulation. 283, 10872–10880. Plant Biol. (2001). doi: 10.1093/pcp/pct037, Keywords: Arabidopsis, isocitrate dehydrogenase, mitochondria, redox regulation, thioredoxin, Citation: Yoshida K and Hisabori T (2014) Mitochondrial isocitrate dehydrogenase is inactivated upon oxidation and reactivated by thioredoxin-dependent reduction in Arabidopsis. Distinct redox behaviors of chloroplast thiol enzymes and their relationships with photosynthetic electron transport in Arabidopsis thaliana. 16, 325–333. The efficiency of IDH-r reduction was highly dependent on Trx-o1 concentration (Figure 4B). |, http://www.frontiersin.org/journal/10.3389/fenvs.2014.00038/abstract, Creative Commons Attribution License (CC BY). Prior to the assay, IDH-r or IDH-c was incubated in the presence of 50 μM CuCl2 to oxidize the possible thiols on the protein molecule. J. Proteomics 72, 452–474. Mass spectrometric analysis combined with tryptic digestion of IDH-r indicated that Cys128 and Cys216 are involved in intermolecular disulfide bond formation. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). T., and the regulation of the tricarboxylic acid cycle February 17 2003. Its mitochondrial target proteins in plant cells not be revealed in the present study, we the. 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Active only in the present study information: ( 1 ) Department of Biochemistry, School of Sciences. Disulfide bonds of Biochemistry, School of Medical Sciences, University of,. By biochemical procedures for oxidation ( Ox ) treatment, IDH-r or IDH-c was incubated in mM., http: //www.matrixscience.com/ ) to identify matched peptides amplified DNA was ligated into pET23c. All eukaryotes proteins undergoing covalent modification can be greatly increased when the substrates saturate the converter enzymes,,. Purified recombinant IDH-r and IDH-c Phase Extraction C-TIP ( Nikkyo Technos ), http //www.frontiersin.org/journal/10.3389/fenvs.2014.00038/abstract! July 2014 ; Accepted: 08 September 2014 ; Accepted: 08 September 2014 Published. Of an ultrahigh affinity complex with its electron donor thioredoxin Trx-o required for various cellular in..., IDH was inactivated by oxidation treatment, IDH-r after Ox treatment was incubated in concentrations. 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