Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.37 (malate dehydrogenase)
 4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

8-Bromo-adenosine diphosphoribose (br8 ADP-Rib) and nicotinamide 8-bromoadenine dinucleotide (Nbr8AD+) which are analogues of the coenzyme NAD+, were prepared and their liver alcohol dehydrogenase complexes studied by crystallographic methods. Nbr8AD+ is active in alcohol dehydrogenase complexes studied by crystallographic methods. Nbr8AD+ is active in hydrogen transport and br8ADP-Rib is a coenzyme competitive inhibitor for the enzymes liver alcohol dehydrogenase and yeast alcohol dehydrogenase. X-ray data were obtained for the complex between liver alcohol dehydrogenase and br8ADP-Rib to 0.45 nm resolution and for the liver alcohol dehydrogenase-adenosine diphosphoribose complex to 0.29-nm resolution. The conformations of these analogues were determined from the X-ray data. It was found that ADP-Rib had a conformation very similar to the corresponding part of NAD+, when NAD+ is bound to lactate and malate dehydrogenase. br8ADP-Rib had the same anti conformation of the adenine ring with respect to the ribose as ADP-Rib and NAD+, in contrast to the syn conformation found in 8-bromo-adenosine. The overcrowding at the 8-position is relieved in br8ADP-Rib by having the ribose in the 2' endo condormation instead of the usual 3' endo as in ADP-Rib and NAD+.
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PMID:The conformation of adenosine diphosphoribose and 8-bromoadenosine diphosphoribose when bound to liver alcohol dehydrogenase. 16 41

Changes in the metabolism of Crithidia fasciculata ATCC 11745 when grown in the presence of ethidium bromide were studied. Ethidium bromide-grown cells had decreased respiratory activity as measured by oxygen consumption. More than 50% of the organisms cultivated in a defined medium containing 1.0 mg/liter of ethidium bromide became dyskinetoplastic and had decreased activities of particulate succinate and NADH-linked dehydrogenases as well as of soluble isocitrate dehydrogenase. These cells also had increased activities of particulate alpha-glycerophosphate dehydrogenase, soluble alpha-glycerophosphate dehydrogenase, malic enzyme, hexokinase, and malate dehydrogenase. Ethidium bromide-grown cells had a lower level of ATP and contained less DNA than cells grown in its absence.
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PMID:Effect of ethidium bromide on the oxidative metabolism and enzyme profiles of Crithidia fasciculata. 86 23

Irradiation with ultraviolet light (360 nm) of cell-free extracts, electron-transport particles, and soluble components from Mycobacterium phlei resulted in the loss of malate oxidation by the flavine adenine dinucleotide pathway both in cell-free extracts and reconstituted systems. Addition of vitamin K1 restored the loss to the extent of 14% and 11% in cell-free extracts and reconstituted systems respectively. Electron-transport particles from M. phlei upon reduction with malate exhibited electron-paramagnetic resonance signals at g = 2.002 and 1.94, characteristic of napthosemiquinone and nonheme iron protein, respectively. Upon irradiating the particles with ultraviolet light (360 nm) these signals were not observed. Particulate flavine-adenine-dinucleotide-dependent malate dehydrogenase (EC 1.1.1.37) of M. phlei assayed by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyl tetrazolium bromide and phenazine methosulfate - 2,6-dichlorophenolindophenol systems, which trap electrons at cytochrome c and at the flavine level respectively, was inhibited by o-phenanthroline. These observations suggest that nonheme iron protein is sensitive to ultraviolet light (360 nm) and participates before or in combination with flavine in the malate (flavine adenine dinucleotide) pathway of M. phlei.
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PMID:Site of action of nonheme iron in the malate (flavine adenine dinucleotide) pathway of Mycobacterium phlei. 96 13

This paper reports the purification and the properties of a thioredoxin from the fungus Aspergillus nidulans. This thioredoxin is an acidic protein which exhibits an unusual fluorescence emission spectrum, characterized by a high contribution of tyrosine residues. Thioredoxin from A. nidulans cannot serve as a substrate for Escherichia coli thioredoxin reductase. Corn NADP-malate dehydrogenase is activated by this thioredoxin in the presence of dithiothreitol, while fructose-1,6-bisphosphatase is not. The amino acid sequence of Aspergillus thioredoxin was determined by automated Edman degradation after cleavage with trypsin, SV8 protease, chymotrypsin and cyanogen bromide. The masses of tryptic peptides were verified by plasma-desorption mass spectrometry. The mass of the protein was determined by electrospray mass spectrometry and shown to be in agreement with the calculated mass derived from the sequence (M(r) = 11,564). Compared to thioredoxins from other sources, the protein from A. nidulans displays a maximal sequence similarity with that from yeast (45%).
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PMID:Purification, properties and primary structure of thioredoxin from Aspergillus nidulans. 145 27

A simple plate-assay has been developed to screen microorganisms for L-malic acid production. Acid producing organisms were identified, after microbial colony growth on media containing glucose or fumaric acid as sole carbons sources, by formation of a dark halo of formazan. The halo was observed when the plate was covered with a soft agar overlay containing NAD(+)-malate dehydrogenase, NAD+, phenazine methosulfate (PMS) and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). The assay developed is simple, specific for L-malic acid and therefore can be used to identify L-malic acid producing filamentous fungi using glucose as carbon source (e.g. Aspergillus strains). The assay is also applicable for screening bacteria with high fumarase activity, able to convert fumaric acid to L-malic acid.
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PMID:A simple plate-assay for the screening of L-malic acid producing microorganisms. 218 83

In order to study the detergent-enzyme interaction and to clarify whether such an interaction produces specific or non-specific effects, we investigated the action of natural and synthetic detergents on enzymatic systems of different levels of complexity (crystalline enzymes, crude homogenates, organ preparations, organisms in toto i.e. rats and germinating seeds). The enzyme-detergent interaction was examined both as a time-independent phenomenon (inhibition) and as a time-dependent phenomenon (inactivation). In in vitro experiments a clear inhibition of pyridine-dependent dehydrogenases by long-chain anionic detergents was found. Cationic detergents have their greatest effect on lipase, LDH, MDH and ICDH from rat liver homogenates. At low concentrations SDS inactivates all the dehydrogenase enzymes studied. With high concentrations (10 mM) of SDS and dodecyltrimethylammonium bromide (C12), there was a sharp and non-specific decrease of enzymatic activities. In the in vivo studies, rats were given detergents to drink; the cationic detergent (C12) was far more effective than SDS with enzymes from both intestine and liver homogenates. SDS and C12 do not seem to interfere with enzyme activities at the beginning of the germination of Pinus pinea and Triticum durum seeds. However a marked reduction of activities does occur at the respective maximum germination times of these seeds. The nonionic detergent is ineffective both as inhibitor and as inactivator.
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PMID:Detergents as selective inhibitors and inactivators of enzymes. 293 71

The thermostability in vitro of dimeric and tetrameric malate dehydrogenases [S)-malate:NAD+ oxidoreductase, EC 1.1.1.37) from mesophilic and thermophilic bacteria shows a good correlation to the growth temperature of the source organism but no consistent relationship to enzyme subunit structure. The thermophile malate dehydrogenases are, in general, more resistant to the surfactants, sodium dodecyl sulphate (SDS) and hexadecyltrimethylammonium bromide, and to the denaturants, guanidinium chloride and urea, than their mesophilic counterparts, with the dimer in each thermal class being more resistant to the chemical perturbants than the tetramer. Sedimentation analysis suggests that denaturation of the malate dehydrogenases by acid-periodate or SDS produces discrete subunits, whereas denaturation by guanidinium chloride followed by carboxymethylation yields ill-defined protein species. SDS and acid-periodate were therefore preferred to generate denatured malate dehydrogenases for use as immunogens and antigens. The native malate dehydrogenases exhibit immunological cross-reactivity only when they are in the same oligomeric form and derived from closely related species, which may, however, be from different thermal classes. Taking immunological cross-reactivity as an indicator of structural similarity, this supports the idea that the thermophilic trait evolved independently within each phyletic line. With denatured malate dehydrogenases as immunogens and antigens, cross-reactivity is manifested between all the malate dehydrogenases examined. This suggests that appreciable primary structural homology exists between the malate dehydrogenases, whether dimeric or tetrameric, from thermophiles and mesophiles and from various taxa.
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PMID:Stability and immunological cross-reactivity of malate dehydrogenases from mesophilic and thermophilic sources. 339 23

The cationic surfactant, cetyl (hexadecyl) trimethylammonium bromide (CTAB), completely inactivates porcine heart cytoplasmic malate dehydrogenase (L-malate:NAD+ oxidoreductase, EC 1.1.1.37) at concentrations (of surfactant) which do not affect the activity of the mitochondrial isoenzyme. These concentrations are close to, or higher than, the critical micelle concentration of CTAB. An increase in the ionic strength of the medium significantly retards the CTAB-induced inactivation of the cytoplasmic enzyme. The enzyme is also markedly protected against CTAB inactivation by NADH; L-malate on its own has no effect but a combination of NADH and L-malate affords greater protection than NADH alone. The CTAB inactivation is not reversed by dilution of the surfactant. The highly selective action of CTAB on the two malate dehydrogenases, which correlates well with their electrostatic charges, has been exploited for a simple and reliable differential assay of these isoenzymes. The anionic surfactant, sodium dodecyl sulphate (SDS), at concentrations well below the critical micelle concentration, inactivates both isoenzymes, but the mitochondrial enzyme is significantly more sensitive than its cytoplasmic counterpart. There is thus some correlation, though not as strong as with CTAB, between SDS inactivation and the charges of the two malate dehydrogenases. An increase in ionic strength has opposite effects on the two isoenzymes: the mitochondrial enzyme becomes more resistant and the cytoplasmic enzyme less so. Both isoenzymes are rendered more resistant to SDS by the inclusion of NADH. Inactivation of the enzymes caused by short exposure to SDS is largely reversed by dilution of the detergent, but longer exposure leads to progressive irreversible loss of activity. NADH very effectively protects the isoenzymes against irreversible inactivation. It is likely that a reversible phase of inactivation precedes an irreversible phase and that in the former phase SDS acts competitively with NADH. Both malate dehydrogenases possess considerable resistance to the nonionic detergent, Triton X-100.
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PMID:Action of surfactants on porcine heart malate dehydrogenase isoenzymes and a simple method for the differential assay of these isoenzymes. 376 4

The effect of different salts and amino acids on the thermal stability and quaternary conformation of pig heart mitochondrial malate dehydrogenase (phm-MDH) in solution has been determined. The effectiveness of salts of anions in the stabilisation of phm-MDH followed the order: Citrate > SO(4)2- > or = Tartrate > Phosphate > F-, CH3COO- > Cl- > Br-. Anions above and including Cl- in this series were increasingly effective in stabilising phm-MDH with a rise in salt concentration from 0.05-2 M, whilst Br- was destabilising under similar conditions. The effect of potassium salts of acetate, chloride and bromide at a concentration of 1 M on the quaternary conformation of phm-MDH correlated also with the relative order of anion stabilisation above, with the anions higher in the series increasingly promoting the formation of the dimeric conformation of the enzyme. The cations of the corresponding salts had a relatively neutral (Cs+, K+, Na+, (CH3)4N+, NH4+) to a destabilising ((CH3)4N+, NH4+, Li+) effect on phm-MDH. Potassium ferrocyanide and potassium ferricyanide conferred complex, concentration dependent effects on the stability of phm-MDH, unlike the salts described above. Salts of amino acids were effective in the stabilisation of phm-MDH against temperature induced changes, following the order: NaGlutamatec = NaAspartate > NaGlycinate > lysine. HCl > arginine. HCl. The magnitudes and trends of the effects of these salts and amino acids on the stability and quaternary structure of phm-MDH were observed to correlate well with considerations based on the Hofmeister series of anions and solvophobic concepts as they apply to the influence of co-solvents at intermediate to higher concentrations. Other, more specific effects were also evident in the stabilisation and destabilisation of phm-MDH by low concentrations of the salts, as noted most particularly in the presence of potassium ferrocyanide and potassium ferricyanide.
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PMID:Stability studies on pig heart mitochondrial malate dehydrogenase: the effect of salts and amino acids. 876 25

The stability of malate dehydrogenase (hMDH) from Halobacterium salinarum in aqueous medium at low salt concentrations (1 and 0.5 M NaCl) was studied at 4 degrees and 25 degrees C. The results showed that hMDH was more stable at the higher salt concentration and the low temperature. hMDH was introduced into reverse micelles of hexadecyltrimethylammonium bromide in cyclohexane with 1-butanol as co-surfactant. The hMDH stability in this system was studied at two omega(0) ([H(2)O]/[surfactant]) values and the effects of salt concentration, presence of substrate and dilution before or after its introduction into reverse micelles were examined. The results showed that the half-life of hMDH dissolved in buffer with 1 M NaCl was 12-50 days in reverse micelles (depending on the various conditions), in contrast to only about 1 day in aqueous medium at 25 degrees C. These observations indicate that reverse micelles provide a microenvironment that allows a much greater stability of this enzyme compared with an aqueous medium.
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PMID:Increased stability of malate dehydrogenase from Halobacterium salinarum at low salt concentration in reverse micelles. 1238 17


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