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Biological Trace Element Research Aug 2009Lactate dehydrogenase (LDH, EC1.1.1.27), widely expressed in the heart, liver, and other tissues, plays an important role in glycolysis and glyconeogenesis. The activity...
Lactate dehydrogenase (LDH, EC1.1.1.27), widely expressed in the heart, liver, and other tissues, plays an important role in glycolysis and glyconeogenesis. The activity of LDH is often altered upon inflammatory responses in animals. Nano-TiO(2) was shown to provoke various inflammatory responses both in rats and mice; however, the molecular mechanism by which TiO(2) exerts its toxicity has not been completely understood. In this report, we investigated the mechanisms of nano-anatase TiO(2) (5 nm) on LDH activity in vitro. Our results showed that LDH activity was greatly increased by low concentration of nano-anatase TiO(2), while it was decreased by high concentration of nano-anatase TiO(2). The spectroscopic assays revealed that the nano-anatase TiO(2) particles were directly bound to LDH with mole ratio of [nano-anatase TiO(2)] to [LDH] was 0.12, indicating that each Ti atom was coordinated with five oxygen/nitrogen atoms and a sulfur atoms of amino acid residues with the Ti-O(N) and Ti-S bond lengths of 1.79 and 2.41 A. We postulated that the bound nano-anatase TiO(2) altered the secondary structure of LDH, created a new metal ion-active site for LDH, and thereby enhanced LDH activity.
Topics: Animals; Coloring Agents; Enzyme Activation; Heart; L-Lactate Dehydrogenase; Myocardium; Nanoparticles; Rats; Titanium
PubMed: 19214398
DOI: 10.1007/s12011-009-8326-9 -
Clinical Chemistry Oct 1982Determination of lactate dehydrogenase (LDH) activity in the SMAC (Technicon) is based on the change in NADH absorbance between two flow cells. We noted that results for...
Determination of lactate dehydrogenase (LDH) activity in the SMAC (Technicon) is based on the change in NADH absorbance between two flow cells. We noted that results for patients' specimens and controls changed when the fiber optic terminations for the two LDH channel flow cells were adjusted or "peaked" at the colorimeter chopper assembly. The energy (intensity) of light reaching the flow cells was varied by adjusting the fiber optic terminations, and the absorbance readings for a series of solutions containing NADH and patients' specimens were recorded. For both flow cells, when the fiber optic terminations were adjusted to increase the zero absorbance light intensity from 20 lines to 60 lines, a significant (p less than 0.0001) proportional change was seen in the absorbance readings. Evidently the difference in absorbance between the two flow cells is related not only to the NADH concentrations but also to the difference in the light intensity at the two flow cells. Consequently, changes in the adjustment of the fiber optic terminations produce systematic changes in results for LDH in patients' sera. These systematic changes in LDH results may be minimized by maintaining equivalent settings of the fiber optic terminations for the two flow cells and by using the calibration material with an absorbance most similar to that of patients' specimens.
Topics: Autoanalysis; Fiber Optic Technology; Humans; L-Lactate Dehydrogenase; Optical Fibers; Spectrophotometry, Ultraviolet
PubMed: 7127739
DOI: No ID Found -
European Journal of Biochemistry Aug 1976The fructose-1,6-bisphosphate-activated L-lactate dehydrogenase (EC 1.1.1.27) from Lactobacillus casei ATCC 393 has been purified to homogenity by including affinity...
The fructose-1,6-bisphosphate-activated L-lactate dehydrogenase (EC 1.1.1.27) from Lactobacillus casei ATCC 393 has been purified to homogenity by including affinity chromatography (cibacronblue-Sephadex-G-200) and preparative polyacrylamide gel electrophoresis into the purification procedures. The enzyme has an Mr of 132000-135000 with a subunit Mr of 34000. The pH optimum was found to be 5.4 insodium acetate buffer. Tris/maleate and citrate/phosphate buffers inhibited enzyme activity at this pH. The enzyme was completely inactivated by a temperature increase from 60 degrees C to 70 degrees C. Pyruvate saturation curves were sigmoidal in the absence of fructose 1,6-bisphosphate. In the presence of 20 muM fructose 1,6-bisphosphate a Km of 1.0 mM for pyruvate was obtained, whereas fructose 1,6-bisphosphate had no effect on the Km of 0.01 mM for NADH. The use of pyruvate analogues revealed two types of pyruvate binding sites, a catalytic and an effector site. The enzyme from L. casei appears to be subject to strict metabolic control, since ADP, ATP, dihydroxyacetone phosphate and 6-phosphogluconate are strong inhibitors. Immunodiffusion experiments with a rabbit antiserum to L. casei lactate dehydrogenase revealed that L. casei ATCC 393 L (+)-lactate dehydrogenase is probably not immunologically related to group D and group N streptococci. Of 24 lactic acid bacterial strains tested only 5 strains did cross-react: L. casei ATCC 393 = L. casei var. rhamnosus ATCC 7469 - L. casei var. alactosus NCDO 680 greater than L. casei UQM 95 greater than L. plantarum ATCC 14917.
Topics: Cations, Divalent; Immunodiffusion; Immunoelectrophoresis; Kinetics; L-Lactate Dehydrogenase; Lacticaseibacillus casei; Macromolecular Substances; Molecular Weight; Pyruvates; Species Specificity; Structure-Activity Relationship; Sulfhydryl Reagents
PubMed: 823016
DOI: 10.1111/j.1432-1033.1976.tb10720.x -
Biology of Reproduction Mar 2021
Topics: Animals; Contraceptive Agents, Male; History, 20th Century; History, 21st Century; Humans; Isoenzymes; L-Lactate Dehydrogenase; Male; Mentoring; Research; Spermatogenesis; United States
PubMed: 33030202
DOI: 10.1093/biolre/ioaa188 -
The Journal of Biological Chemistry Jan 1978
Topics: Animals; Half-Life; Isoenzymes; Kidney; L-Lactate Dehydrogenase; Liver; Male; Mice; Muscles; Phenotype
PubMed: 618856
DOI: No ID Found -
Proteins Feb 2010Lactobacillus casei L-lactate dehydrogenase (LCLDH) is activated through the homotropic and heterotropic activation effects of pyruvate and fructose 1,6-bisphosphate...
Lactobacillus casei L-lactate dehydrogenase (LCLDH) is activated through the homotropic and heterotropic activation effects of pyruvate and fructose 1,6-bisphosphate (FBP), respectively, and exhibits unusually high pH-dependence in the allosteric effects of these ligands. The active (R) and inactive (T) state structures of unliganded LCLDH were determined at 2.5 and 2.6 A resolution, respectively. In the catalytic site, the structural rearrangements are concerned mostly in switching of the orientation of Arg171 through the flexible intersubunit contact at the Q-axis subunit interface. The distorted orientation of Arg171 in the T state is stabilized by a unique intra-helix salt bridge between Arg171 and Glu178, which is in striking contrast to the multiple intersubunit salt bridges in Lactobacillus pentosus nonallosteric L-lactate dehydrogenase. In the backbone structure, major structural rearrangements of LCLDH are focused in two mobile regions of the catalytic domain. The two regions form an intersubunit linkage through contact at the P-axis subunit interface involving Arg185, replacement of which with Gln severely decreases the homotropic and hetertropic activation effects on the enzyme. These two regions form another intersubunit linkage in the Q-axis related dimer through the rigid NAD-binding domain, and thus constitute a pivotal frame of the intersubunit linkage for the allosteric motion, which is coupled with the concerted structural change of the four subunits in a tetramer, and of the binding sites for pyruvate and FBP. The unique intersubunit salt bridges, which are observed only in the R state structure, are likely involved in the pH-dependent allosteric equilibrium.
Topics: Amino Acid Sequence; Catalytic Domain; Crystallography, X-Ray; Fructose-Bisphosphatase; L-Lactate Dehydrogenase; Lacticaseibacillus casei; Models, Molecular; Molecular Sequence Data; Mutation; Protein Binding; Protein Conformation; Sequence Alignment
PubMed: 19787773
DOI: 10.1002/prot.22597 -
Biochimica Et Biophysica Acta Oct 1995Ellman's reagent, 5,5'-dithiobis(2-nitrobenzoic acid), has been used to titrate D-lactate dehydrogenase (D-LDH), a respiratory flavoenzyme of Escherichia coli. All six...
Ellman's reagent, 5,5'-dithiobis(2-nitrobenzoic acid), has been used to titrate D-lactate dehydrogenase (D-LDH), a respiratory flavoenzyme of Escherichia coli. All six of the possible sulfhydryls titrate in the presence of 2% sodium dodecylsulfate, showing that D-lactate dehydrogenase does not contain any -S-S- bridges. In the native state, only two sulfhydryls are accessible in buffer and only one in the presence of lipid. Single-site mutations of each of the six cysteines of D-lactate dehydrogenase have been prepared. Each of the purified mutant proteins has full activity, demonstrating that an -SH group is not essential to the FAD-driven redox reaction. Ellman's titrations of the mutant proteins have led to the identification of cysteines 65, 146, 156, and 256 in the amino-terminal end as those containing the sulfhydryls that are not accessible in buffer or in buffer plus lipid. The cysteine at 422 is titrated only partially in buffer, while in buffer containing lipid, a necessary factor for full enzymatic activity, its sulfhydryl is inaccessible to the reagent. Cysteine 492 has been identified as containing the sulfhydryl that is accessible to the reagent under both conditions.
Topics: Bacterial Outer Membrane Proteins; Cysteine; Disulfides; Dithionitrobenzoic Acid; Escherichia coli; Kinetics; L-Lactate Dehydrogenase; Mutagenesis, Site-Directed; Nitrobenzoates; Serine; Sulfhydryl Compounds; Sulfhydryl Reagents
PubMed: 7578234
DOI: 10.1016/0167-4838(95)00121-a -
Journal of Oral Surgery (American... Nov 1967
Topics: Animals; Bone Regeneration; Electrophoresis; Isoenzymes; L-Lactate Dehydrogenase; Mandible; Rabbits; Spectrophotometry
PubMed: 5233344
DOI: No ID Found -
Experimental Parasitology Oct 2008Plasmodium lactate dehydrogenase (pLDH), owing to unique structural and kinetic properties, is a well known target for antimalarial compounds. To explore a new approach...
Plasmodium lactate dehydrogenase (pLDH), owing to unique structural and kinetic properties, is a well known target for antimalarial compounds. To explore a new approach for high level soluble expression of Plasmodium falciparum lactate dehydrogenase (PfLDH) in E. coli, PfLDH encoding sequence was cloned into pQE-30 Xa vector. When transformed E. coli SG13009 cells were induced at 37 degrees C with 0.5mM isopropyl beta-d-thiogalactoside (IPTG) concentration, the protein was found to be exclusively associated with inclusion bodies. By reducing cell growth temperature to 15 degrees C and IPTG concentration to 0.25 mM, it was possible to get approximately 82% of expressed protein in soluble form. Recombinant PfLDH (rPfLDH) was purified to homogeneity yielding 18 mg of protein/litre culture. rPfLDH was found to be biologically active with specific activity of 453.8 micromol/min/mg. The enzyme exhibited characteristic reduced substrate inhibition and enhanced k(cat) [(3.2+/-0.02)x10(4)] with 3-acetylpyridine adenine dinucleotide (APAD+). The procedure described in this study may provide a reliable and simple method for production of large quantities of soluble and biologically active PfLDH.
Topics: Animals; Blotting, Western; Chromatography, Gel; Cloning, Molecular; DNA, Protozoan; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Gene Expression Regulation, Enzymologic; Humans; Kinetics; L-Lactate Dehydrogenase; Plasmodium falciparum; Rabbits; Temperature
PubMed: 18619439
DOI: 10.1016/j.exppara.2008.06.006 -
European Journal of Clinical Chemistry... Aug 1994
Approved recommendation on IFCC methods for the measurement of catalytic concentration of enzymes. Part 8. IFCC Method for Lactate Dehydrogenase (l-Lactate: NAD+Oxidoreductase, EC 1.1.1.27). International Federation of Clinical Chemistry (IFCC).
Topics: Catalysis; Chemistry, Clinical; Humans; L-Lactate Dehydrogenase
PubMed: 7819436
DOI: No ID Found