• Title/Summary/Keyword: Dehydrogenases

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Isocitrate dehydrogenase mutations: new opportunities for translational research

  • Keum, Young-Sam;Choi, Bu Young
    • BMB Reports
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    • v.48 no.5
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    • pp.266-270
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    • 2015
  • Over the last decade, comprehensive genome-wide sequencing studies have enabled us to find out unexpected genetic alterations of metabolism in cancer. An example is the identification of arginine missense mutations of isocitrate dehydrogenases-1 and -2 (IDH1/2) in glioma, acute myeloid leukemia (AML), chondrosarcomas, and cholangiocarcinoma. These alterations are closely associated with the production of a new stereospecific metabolite, (R)-2-hydroxyglutarate (R-2HG). A large number of follow-up studies have been performed to address the molecular mechanisms of IDH1/2 mutations underlying how these events contribute to malignant transformation. In the meanwhile, the development of selective mutant IDH1/2 chemical inhibitors is being actively pursued in the scientific community and pharmaceutical industry. The present review article briefly discusses the important findings that highlight the molecular mechanisms of IDH1/2 mutations in cancer and provides a current status for development of selective mutant IDH1/2 chemical inhibitors. [BMB Reports 2015; 48(5): 266-270]

Purification and characterization of a thermostable glutamate dehydrogenase from a thermophilic bacterium isolated from a sterilization drying oven

  • Amenabar, Maximiliano J.;Blamey, Jenny M.
    • BMB Reports
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    • v.45 no.2
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    • pp.91-95
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    • 2012
  • Glutamate dehydrogenase from axenic bacterial cultures of a new microorganism, called GWE1, isolated from the interior of a sterilization drying oven, was purified by anion-exchange and molecular-exclusion liquid chromatography. The apparent molecular mass of the native enzyme was 250.5 kDa and was shown to be an hexamer with similar subunits of molecular mass 40.5 kDa. For glutamate oxidation, the enzyme showed an optimal pH and temperature of 8.0 and $70^{\circ}C$, respectively. In contrast to other glutamate dehydrogenases isolated from bacteria, the enzyme isolated in this study can use both $NAD^+$ and $NADP^+$ as electron acceptors, displaying more affinity for $NADP^+$ than for $NAD^+$. No activity was detected with NADH or NADPH, 2-oxoglutarate and ammonia. The enzyme was exceptionally thermostable, maintaining more than 70% of activity after incubating at $100^{\circ}C$ for more than five hours suggesting being one of the most thermoestable enzymes reported in the family of dehydrogenases.

Application of Poly (Ethylene Glycol)-Bound NAD in Model Enzyme Reactor

  • Urabe, Itaru
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 1986.12a
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    • pp.510.1-510
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    • 1986
  • Many enzymes require the participation of readily dissociable coenzymes as NAD for thir catalytic activities. The continuous utilization of the enzymes requires the retention and regeneration of the coenzymes. For this purpose, several kinds of macromolecular NAD derivatives have been prepared by covalently attaching NAD to watersoluble polymers. We have prepared poly (ethylene glycol)-bound NAD (PEG-NAD) by coupling N$\^$6/-(2-carboxyethyl)-NAD to one terminal of ${\gamma}$ $\omega$-diaminoly (ethylene glycol) (Mr 3000) with water-soluble carbodiimide. PED-NAD thus obtained has one NAD moiety located at a terminal of the linear, flexible and hydrophilic chain of poly (ethylene glycol). PED-NAD has good coenzyme activity for various dehydrogenases and is applicable in a continuous enzyme reactor. To use these macromolecular NAD derivatives in an enzyme reactor, it si necessary to understand the behavior of the system in which the reactions of dehydrogenases are coupled by the recycling of the NAD derivative. We investigated the kinetic properties of a continuous enzyme reactor containing lactate dehydrogenase, alcohol dehydrogenase and PEG-NAD. The steady-state behavior of the enzyme reactor is explained by a simple kinetic model.

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Effects of Mercuric Chloride on the Differentiation Cerebral Neuron of Chick Embryo (II) (계배 대뇌의 신경세포 분화에 미치는 수은의 영향 (II))

  • Kim, Saeng-Gon;Jeong, Hae-Man;Cho, Kwang-Phil
    • Applied Microscopy
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    • v.26 no.3
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    • pp.253-266
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    • 1996
  • To investigate the effects of mercuric chloride ($HgCl_2$) on the differentiation of the cerebral neuron of chick embryo 9 days, the ultrastructural changes in nerve cells injected with a various doses of mercuric chloride were observed with transmission electron microscope. The enzyme activity of the some dehydrogenases, cerebral proteins and adenosine triphosphate (ATP) were also analyzed. The results obtained are as follows: The ultrastructural changes in 0.5 and 1.0mg-injected groups were undetectable, but in 2.0mg-injected group, the nuclear envelops were very irregular and mitochondria, were swelled and destroyed partly. The number of polypeptide bands separated by SDS-PAGE in the normal group were 37 bands. According to the in creased dose of mercuric chloride, contends of the bands were increased in 7 bands. The activities of dehydrogenases were declined by increasing the dose of mercuric chloride. Lactate dehydrogenase (LDH) activity failed to 78% in 1.0mg-injected group and greatly to 68% in 2.0 mg-injected group. Malate dehydrogenase (MDH) activity failed to 81% in 2.0 mg-injected group. On the other hand, succinate dehydrogenase (SDH) activity decreased to 80% in 1.0 mg-injected group and greatly to 63% in 2.0 mg-injected group. ATP content in 1.0 mg-injected group was increased slightly and in 2.0 mg-injected group was increased greatly.

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Purification and Characterization of a Cyclohexanol Dehydrogenase from Rhodococcus sp. TK6

  • Kim, Tae-Kang;Choi, Jun-Ho;Rhee, In-Koo
    • Journal of Microbiology and Biotechnology
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    • v.12 no.1
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    • pp.39-45
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    • 2002
  • Activity staining on the native polyacrylamide gel electrophoresis (PAGE) of a cell-free extract of Rhodococcus sp. TK6, grown in media containing alcohols as the carbon source, revealed at least seven isozyme bands, which were identified as alcohol dehydrogenases that oxidize cyclohexanol to cyclohexanone. Among the alcohol dehydrogenases, cyclohexanol dehydrogenase II (CDH II), which is the major enzyme involved in the oxidation of cyclohexanol, was purified to homogeneity. The molecular mass of the CDH II was determined to be 60 kDa by gel filtration, while the molecular mass of each subunit was estimated to be 28 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The CDH II was unstable in acidic and basic pHs, and rapidly inactivated at temperatures above $40^{\circ}C$ . The CDH II activity was enhanced by the addition of divalent metal ions, like $Ba^2+\;and\;Mg^{2+}$. The purified enzyme catalyzed the oxidation of a broad range of alcohols, including cyclohexanol, trans-cyclohexane-1,2-diol, trans-cyclopentane-l,2-diol, cyclopentanol, and hexane-1,2-diol. The $K_m$ values of the CDH II for cyclohexanol, trans-cyclohexane-l,2-diol, cyclopentanol, trans-cyclopentane-l,2-diol, and hexane-l,2-diol were 1.7, 2.8, 14.2, 13.7, and 13.5 mM, respectively. The CDH II would appear to be a major alcohol dehydrogenase for the oxidation of cyclohexanol. The N-terminal sequence of the CDH II was determined to be TVAHVTGAARGIGRA. Furthermore, based on a comparison of the determined sequence with other short chain alcohol dehydrogenases, the purified CDH II was suggested to be a new enzyme.

Effects of Mercury on the Differentiation Cerebral Neuron of Chick Embry (III) (수은이 계배 대뇌의 신경세포 분화에 미치는 영향(III))

  • Jeong, Hae-Man;Kim, Saeng-Gon;Cho, Kwang-Phil
    • Applied Microscopy
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    • v.27 no.1
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    • pp.87-100
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    • 1997
  • To investigate the effects of mercuric chloride $(HgCl_2)$ on the differentiation of the cerebral neuron of chick embryo 10 days, the ultrastructural changes in nerve cells injected with a various doses of mercuric chloride were observed with transmission electron microscope. The enzyme activity of the some dehydrogenases, cerebral proteins and adenosine triphosphate (ATP) were also analyzed. The results obtained are as follows; The ultrastructural changes in 1.0 mg-injected group, the nuclear membranes were irregular, outer of mitochondria membrances dispressioned, their cristae were destroyed. In 2.0 mg-injected group, the nuclear envelops were destroyed and divided, were not observed organelle except of few ribosome, the RER and mitochondria. The number of polypeptide bands were separated by SDS-PAGE in the normal group were 38 bands. According to the in creased dose of mercuric chloride, contends of the bands were increased in 4 bands, but were decreased in 1 band. The activities of dehydrogenases were declined by increasing the dose of mercuric chloride. Lactate dehydrogenase (LDH) activity fatted to 61% in 2.0 mg-injected group. Malate dehydrogenase (MDH) activity fatted to 90% in 1.0 mg-injected group, greatly to 76% in 2.0 mg-injected group. Succinate dehydrogenase (SDH) activity decreased to 79% in 1.0 mg-injected group and greatly to 62% in 2.0 mg-injected group. ATP content in 1.0 mg-injected group was almost near to the normal level, but it was increased greatly in 2.0 mg-injected group.

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Enzymological Localization of Carbon Monoxide Dehydrogenases in Pseudomonas carboxydovorans and Acinetobacter sp.1 (Pseudomonas carboxydovorans와 Acinetobacter sp.1의 일산화탄소 산화효소의 세포내 분포에 대한 효소학적 연구)

  • 김시욱;김영민
    • Korean Journal of Microbiology
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    • v.24 no.3
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    • pp.270-275
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    • 1986
  • The localization of carbon monoxide dehydrogenases (CO-DHs) in Pseudomonas carvoxydovorans and Acinetobacter sp.1 was examined by comparison of the distribution of CO-oxidizing activity between soluble and particulate fractions obtained after disruption of CO-grown cells by sonic oscillation and of spheroplasts by osmotic shock. When the cells were broken by sonic oscillation, most of the CO-DH activity was recovered from soluble fractions. However, disryption by osmotic lysis of spheroplasts revealed that the enzyme activity is present in the cell membrane. The results indicated the CO-DHs in these cells are loosely attached to the cytoplasmic membrane.

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