radiation inactivation of glutamate and isocitrate dehydrogenases. by Radwan Rashad Abu El Failat

Cover of: radiation inactivation of glutamate and isocitrate dehydrogenases. | Radwan Rashad Abu El Failat

Published by University of Salford in Salford .

Written in English

Read online

Edition Notes

PhD thesis, Biochemistry.

Book details

SeriesD37948/81
ID Numbers
Open LibraryOL19685821M

Download radiation inactivation of glutamate and isocitrate dehydrogenases.

The radiation inactivation of glutamate and isocitrate dehydrogenases. (Thesis) Abu El Failat RR. Publisher: University of Salford [] Metadata Source: The British Library Type: Thesis.

Abstract. No abstract supplied. Menu. Formats. Abstract. EThOS. About. About Europe PMC; Funders Author: Abu El Failat Rr. The radiation inactivation of glutamate and isocitrate dehydrogenases Author: Abu El Failat, R. ISNI: Awarding Body: University of Salford Current Institution: University of Salford Date of Award: Availability of Full Text: Author: Abu El Failat.

The effects of ionizing radiation on glutamate dehydrogenase and on fluorescein isothiocyanate--tagged glutamate dehydrogenase were analyzed by target theory. Enzymatic activity, fluorescence, and the survival of dalton monomer subunit were determined on frozen samples irradiated at degrees C and on lyophilized samples irradiated at either degrees C or +30 Cited by: NADH.

Isocitrate dehydrogenase was assayed by following the reduction of nicotinamide adenine di-nucleotide (NAD) at nmin the presence ofiso-citrate (24). Chromatography. For identification of glutamate, the standardreaction mixture (Table 1) wasextracted with hot ethyl alcohol as described by Flipse and Dietz (11) and was subjected to one.

The effects of ionizing radiation on glutamate dehydrogenase and on fluorescein isothiocyanate--tagged glutamate dehydrogenase were analyzed by target theory. Enzymatic activity, fluorescence, and the survival of dalton monomer subunit were determined on frozen samples irradiated at - degrees C and on lyophilized samples irradiated at either - degrees C or +30 degrees by: Glutamate synthesis has been reported to occur by mechanisms other than those utilizing isocitrate dehydrogenase, a tricarboxylic acid cycle enzyme not previously detected in this organism.

We have recovered α-ketoglutarate and glutamate from a system containing citrate, nicotinamide adenine dinucleotide (NAD), a divalent cation, pyridoxal. Regulation of human glutamate dehydrogenases: Implications for glutamate, ammonia and energy metabolism in brain.

Andreas Plaitakis. Corresponding Author. E-mail address: [email protected] Department of Neurology, University of Crete, School of Health. Glutamate dehydrogenase (GLDH, GDH) is an enzyme observed in both prokaryotes and eukaryotic aforementioned reaction also yields ammonia, which in eukaryotes is canonically processed as a substrate in the urea lly, the α-ketoglutarate to glutamate reaction does not occur in mammals, as glutamate dehydrogenase equilibrium favours the production of ammonia and.

Isocitrate dehydrogenases carry out the oxi-dative decarboxylation of isocitrate (a C6 compound) to give the C5 organic acid, 2-oxoglutarate.

The substrate is an isocitrate-metal ion complex (either Mn 2+ or Mg 2+), which is initially oxidized to oxalosuccinate, bringing about the reduction of a co-factor (NAD or NADP depending on the type of. Glutamate Dehydrogenases: Enzymology, Physiological Role and Biotechnological Relevance.

By Eduardo Santero, Ana B. Hervás, Ines Canosa and Fernando Govantes. Submitted: December 1st Reviewed: May 3rd Published: November 14th DOI: / Glutamate dehydrogenase (GDH) is located in the mitochondria and is an important branch-point enzyme between carbon and nitrogen metabolism.

GDH catalyzes the reversible NAD (P) +-linked oxidative deamination of L-glutamate into alpha ketoglutarate and ammonia in two steps. The first step involves a Schiff base intermediate being formed between ammonia and alpha ketoglutarate.

Andreas Plaitakis, Cleanthe Spanaki, Vasilis Mastorodemos, Ioannis Zaganas, Study of structure–function relationships in human glutamate dehydrogenases reveals novel molecular mechanisms for the regulation of the nerve tissue-specific (GLUD2) isoenzyme, Neurochemistry International, /S(03), 43,(), ().

Glutamate is the primary excitatory neurotransmitter in brain. This neurotransmitter has essential roles in normal brain function including learning and memory. Metabolism of glutamate involves the coordinated activity of astrocytes and neurons and high affinity transporter proteins that are selectively distributed on these cells.

In contrast to glutamate dehydrogenases in ani- mals, those from other organisms are specific for either NAD or NADP and appear not to be regulated by purine nucleotides in physiological concentrations [3].

From the comparison of the primary structure between liver enzymes and the NADP-dependent enzyme from. The isocitrate dehydrogenases (ICDs) catalyse the oxidative decarboxylation of isocitrate to alpha-ketoglutarate and can use either NAD(+) or NADP(+) as a cofactor.

Glutamate Dehydrogenase (GDH) catalyzes the oxidative conversion of glutamate to alpha ketoglutarate and ammonium supplying the TCA cycle with intermediates in support of anaplerosis (Figure 1 Rxn1).Conversely GDH catalyzes the reductive amination of alpha ketoglutarate and ammonium producing glutamate when the TCA cycle pool is filled.

“Glutamate dehydrogenases have been isolated and sequenced from a number of sources and fall into two oligomeric classes. The bacterial and fungal NADP +-linked and vertebrate dual-specificity [proteins] have six identical subunits” whereas “the NAD +-linked enzymes have either four identical subunits” or six identical subunits In each subunit two domains parted by a profound cleft are.

Normal Biochemistry of Isocitrate Dehydrogenases. Isocitrate dehydrogenase (IDH) enzymes catalyze the oxidative decarboxylation of isocitrate to form α-ketoglutarate (αKG), using NADP + as a cofactor to generate NADPH during catalysis. IDH1 and IDH2 proteins share a high degree of sequence similarity (70% in humans) and are encoded by distinct genes (IDH1, 2q33; IDH2, 15q26).

Mutated IDH1 catalyzes isocitrate to 2-hydroxyglutarate (2-HG), which is structurally similar to glutamate, instead of α-ketoglutarate in the Krebs cycle. The accumulation of 2-HG can activate N-methyl-d-aspartate (NMDA) receptors and promote tumor-associated epilepsy (Liubinas et al., ).

Glutamate, a known “tumor growth factor” in. Abstract. Dysregulation of metabolism is a common phenomenon in cancer cells.

The NADP +-dependent isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) function at a crossroads of cellular metabolism in lipid synthesis, cellular defense against oxidative stress, oxidative respiration, and oxygen-sensing signal review the normal functions of the encoded enzymes.

Heterozygous mutations in catalytic arginine residues of isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) are common in glioma, acute myeloid leukemia, chondrosarcoma, cholangiocarcinoma, and angioimmunoblastic T-cell lymphoma.

The mutant enzymes acquire a neomorphic activity that converts α-ketoglutarate (α-KG) to Dhydroxyglutarate (D2HG), a rare metabolite. The radiation inactivation of the modifying effects of ADP, GTP, sodium chloride, sulfhydryl blocking and substrate inhibition was measured.

When assayed with glutamate as substrate, the different allosteric functions had the same or higher radiosensitivity than the catalytic activity. Isotope effect studies of the role of the metal ions in isocitrate dehydrogenase. Biochemistry16 (6), DOI: /bia Gerhard W. Plaut, Richard L. Beach, and Tadashi Aogaichi.

Substrate activity of structural analogs of isocitrate for isocitrate dehydrogenases from bovine heart. L-glutamate by TPN and glutamate dehydrogenase.

These are: (a) an initial rapid production of blue-shifted reduced nicotinamide absorption in the burst phase, (b) a considerably slower production of red-shifted reduced nicotinamide absorption, and finally, (c) the production of free TPNH in the steady state.

THE GDH REACTION. GDH catalyzes the reaction NAD(P) + Glutamate ⇆ NAD(P)H + α-ketoglutarate + NH 4 + ().The catalytically active form of the enzyme is six identical × 10 4 molecular weight monomers configured as a hexamer (11–13).When the concentration of the hexamer is high, it polymerizes (12,13).In addition to possessing binding sites for substrates and products, the enzyme.

NADP(+)-dependent isocitrate dehydrogenase (E.C. ; IDH) is an enzyme of the Krebs cycle and catalyzes the oxidative decarboxylation reaction from DL-isocitrate to alpha-ketoglutarate, with. NAD-isocitrate dehydrogenase (NAD-IDH) from the eukaryotic microalga Chlamydomonas reinhardtii was purified to electrophoretic homogeneity by successive chromatography steps on Phenyl-Sepharose, Blue-Sepharose, diethylaminoethyl-Sephacel, and Sephacryl S (all Pharmacia Biotech).

The kD enzyme was found to be an octamer composed of kD subunits. Calcium plays a key role in activating three mitochondrial dehydrogenases, pyruvate dehydrogenase (PDH), isocitrate dehydrogenase and α-KGDH in the –10 μM range (Denton et al.

; Denton & McCormack ) and by this, in adjusting the rate of metabolism to an increased tion of these dehydrogenases could increase the supply of NADH to the respiratory.

Soundar, S., and Colman, R. F.,Identification of metal-isocitrate binding site of pig heart NADP-specific dehydrogenase by affinity cleavage of the enzyme by Fe 2+-isocitrate, J.

Biol. Chem. – PubMed Google Scholar. Isocitrate dehydrogenases (IDHs) are critical metabolic enzymes that catalyze the oxidative decarboxylation of isocitrate to α-ketoglutarate (αKG), NAD(P)H, and CO2. IDHs epigenetically control gene expression through effects on αKG-dependent dioxygenases, maintain redox balance and promote anaplerosis by providing cells with NADPH and precursor substrates for macromolecular synthesis.

Dysregulation of metabolism is a common phenomenon in cancer cells. The NADP +-dependent isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) function at a crossroads of cellular metabolism in lipid synthesis, cellular defense against oxidative stress, oxidative respiration, and oxygen-sensing signal review the normal functions of the encoded enzymes, frequent.

Aldehyde dehydrogenase enzymes (ALDHs) catalyze the oxidation of aliphatic and aromatic aldehydes to their corresponding carboxylic acids using NAD+ or NADP+. Monomeric isocitrate dehydrogenases (IDHs) have a single polypeptide sizing around 85 kDa.

The IDH2 from the opportunistic bacterium Acinetobacter baumannii (AbIDH2) with a mass of 83 kDa was formerly recognized as a typical monomeric IDH.

However, both size exclusion chromatography and analytical ultracentrifugation analysis indicated that AbIDH2 exists as a homodimer in solution. Bifidobacterium longum is a very important gram-positive non-pathogenic bacterium in the human gastrointestinal tract for keeping the digestive and immune system healthy.

Isocitrate dehydrogenase (IDH) from B. longum (BlIDH), a novel member in Type II subfamily, was overexpressed, purified and biochemically characterized in detail.

The active form of BlIDH was an kDa homodimer. Inactivation of pig heart NADP-specific isocitrate dehydrogenase by two affinity reagents is due to reaction with a cysteine not essential for function. Archives of Biochemistry and Biophysics(2).

Isocitrate Dehydrogenase: An enzyme of the oxidoreductase class that catalyzes the conversion of isocitrate and NAD+ to yield 2-ketoglutarate, carbon dioxide, and occurs in cell mitochondria.

The enzyme requires Mg2+, Mn2+; it is activated by ADP, citrate, and Ca2+, and inhibited by NADH, NADPH, and ATP. isocitrate dehydrogenase. Wikipedia. Medical Information Search.

Five isocitrate dehydrogenases have been reported: three NAD(+)-dependent isocitrate dehydrogenases, which localize to the Isocitrate dehydrogenase [NADP], mitochondrial is an enzyme that in humans is encoded by the IDH2 rate Isocitrate dehydrogenase is a digestive enzyme that is used in the citric acid cycle.

NADP+-dependent isocitrate dehydrogenase is a member of the β-decarboxylating dehydrogenase family and catalyzes the oxidative decarboxylation reaction from 2R,3S-isocitrate to yield 2-oxoglutarate and CO2 in the Krebs cycle.

Although most prokaryotic NADP+-dependent isocitrate dehydrogenases (IDHs) are homodimeric enzymes, the monomeric IDH with a molecular weight of 80– kDa has. Abstract. In extension of a previous study with yeast glucoseP dehydrogenase (Kawaguchi, A., and Bloch, K.

() J. Biol. Chem.), the structural changes accompanying the inhibition of glutamate dehydrogenase and several malate dehydrogenases by palmitoyl-CoA and by sodium dodecyl sulfate have been investigated. Popova OV, Popova TN, Izmailov SF. NAD- and NADP-isocitrate dehydrogenases and glutamate decarboxylase of pea seedlings as affected by salinity stress.

Russ. Plant Physiol. Potrykus J, White RL, Bearne SL. Proteomic investigation of amino acid catabolism in the indigenous gut anaerobe Fusobacterium varium.

NADP+-isocitrate dehydrogenase (NADP+-IDH; EC ) is involved in the supply of 2-oxoglutarate for ammonia assimilation and glutamate synthesis in higher plants through the glutamine synthetase/glutamate synthase (GS/GOGAT) cycle.

Only one NADP+-IDH form of cytosolic localization was detected in green cotyledons of pine (Pinus spp.) seedlings.L-glutamic dehydrogenase catalyzes the conversion of glutamate to α-ketoglutarate.

Unit Definition One unit will reduce μmole of α-ketoglutarate to L-glutamate per min at pH at 25 °C, in the presence of ammonium ions. Physical form 50% glycerol solution Analysis Note Protein determined by biuret.Abstract.

Isocitrate dehydrogenase 2 (IDH2) is located in the mitochondrial matrix. IDH2 acts in the forward Krebs cycle as an NADP+-consuming enzyme, providing NADPH for maintenance of the reduced glutathione and peroxiredoxin systems and for self-maintenance by reactivation of cystine-inactivated IDH2 by glutaredoxin 2.

51178 views Wednesday, December 2, 2020