Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LACTATE DEHYDROGENASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1992

Suppression of development of diabetes in NOD mice by lactate dehydrogenase virus infection.

It has been reported that lactate dehydrogenase virus (LDV) selectively infects a subpopulation of macrophages, thereby affecting the immune system. We studied the effects of LDV infection on the development of diabetes in non-obese diabetic (NOD) mice. Five-week-old female NOD mice were infected with LDV (10(8) ID50/mouse) and observed until 23 weeks of age. None of the 21-LDV-infected mice developed diabetes, whereas 10/14 (71.4%) uninfected mice did. Although the subpopulations of T cells and the percentage of Mac1-positive cells in the NOD murine spleen and the number of harvested peritoneal macrophages were unaffected by LDV infection, the proportions of Ia-positive peritoneal macrophages were significantly decreased in LDV-infected compared with uninfected mice (1.1 +/- 0.2%, 6.5 +/- 2.9%; P < 0.01). In LDV-infected NOD mice, insulitis of the same grade as that seen in uninfected NOD mice was observed. In another experiment, 3, 5, 10 or 16-week-old female NOD mice were infected with LDV. None of the mice infected with LDV at 3, 5 or 10 weeks of age developed diabetes and only one of six infected at 16 weeks of age did. These findings indicate that LDV infection suppresses the development of diabetes in female NOD mice by reducing the capacity of Ia-positive macrophages, and suggest that the development of human type 1 diabetes may be suppressed by certain viral infections.

Animals↗
PubMed1985

The rates of defined changes in protein structure during the catalytic cycle of lactate dehydrogenase.

Rapid mixing, kinetic experiments were performed on native and modified [Tyr(3NO2)237)] porcine H4 lactate dehydrogenase at low temperatures in a medium containing 30% dimethyl sulphoxide. In the temperature range -16 to +8 degrees C, the modified enzyme-NADH complex, when mixed with 1 mM pyruvate, is converted to enzyme, NAD+ and lactate at two distinctly different rates. At -16 degrees C the more rapid process occurs at a rate of 40 s-1 and the slower at 3 s-1. The slower rate is identical to that assigned to the steady-state turnover of the enzyme in these conditions and therefore reflects the slow, rate-limiting rearrangement of protein structure which has been inferred from previous kinetic experiments. The fast phase of NADH oxidation, however, proceeds at a rate which coincides with that of the closure of a loop of polypeptide over the active site of the enzyme (sensed by the nitrotyrosine group, which protonates in response to the approach of glutamate 107, a residue situated on this mobile loop). We explain these results by proposing that: (i) both the slow and fast changes in protein structure must occur before the enzyme can accomplish the redox step, (ii) the enzyme-NADH (binary) complex exists in two, slowly interconverting forms, (iii) the structural change giving rise to this slow conformational equilibrium can also occur in the ternary (enzyme-NADH-pyruvate) complex and (iv) it is this step which limits the rate of the steady-state reaction. Both of the binary forms are able to bind pyruvate, but the rate of NADH oxidation in one of the forms is rapid, since it has already undergone this slow rearrangement. In this rapidly reacting form, it is the closure of the loop (not transfer of the hydride ion) which limits the rate at which the coenzyme is oxidized, while the slowly reacting form must undergo both loop-closure and the slow structural conversion before the redox reaction can occur.

Animals↗
PubMedDate not supplied

[Effect of thyroxine on the lactate dehydrogenase isoenzyme composition of chicken tissues in ontogeny].

Using disc electrophoresis in polyacrylamide gel, studies have been made on the content of isoenzymes of lactate dehydrogenase in the mitochondria and cytoplasm from the brain, heart and liver after thyroxine administration to embryonal, early postnatal and adult hens. After this administration, the isoenzymic composition becomes more complex, redistribution of separate isozymes being observed in ontogenesis. The level of aerobic form of LDH increases at early stages of ontogenesis, that of anaerobic ones--in adult birds. Basing on their different functional role due to the presence of H- and M-subunits, it may be suggested that thyroxine administration results in a compensatory increase of the oxidative or glycolytic processes at the corresponding stages of ontogenesis, these changes reflecting phylogenetic peculiarities of the formation of the hormonal control of lactate dehydrogenase in tissues of birds.

Animals↗
PubMed1975

[Activity of lactate dehydrogenase in the milk serum of dairy cows in relation to the possitive response to the mastitis NK-test].

The level of total lactate dehydrogenase activity in dairy cow milk serum was studied in sets of quarter-udder milks showing different degrees of a positive response to Mastitis test-NK. The bacteriological examination for Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Staphylococcus aureus, and for coliform germs was performed at the same time. Increasing positiveness of the response to Mastitis test-NK was found to be accompanied by an almost proportionate increase of the total lactate dehydrogenase activity level in milk serum. The bacteriological finding was not correlated with increasing positiveness of the response to Mastitis test-NK. New aspects of various diseases of the mammary gland and the possibility to diagnose mainly the latent stages of these diseases are analysed in a discussion.

Animals↗
PubMed1980

Concurrent measurements of carcinoembryonic antigen, glucosephosphate isomerase, gamma-glutamyltransferase, and lactate dehydrogenase in malignant, normal adult, and fetal colon tissues.

Carcinoembryonic antigen and activities of glucosephosphate isomerase (EC 5.3.1.9), gamma-glutamyltransferase (EC 2.3.2.2), and lactate dehydrogenase (EC 1.1.1.27) were measured in aqueous extracts of fetal, normal adult, and malignant human colon tissues. Fetal colon, as well as primary and metastatic colon tumor tissue, showed higher activities of these analytes than did normal adult human colon. Liver metastases of colon cancer gave the highest values, normal adult human colon the lowest. Statistically, these differences were more striking in the case of carcinoembryonic antigen and glucosephosphate isomerase than for gamma-glutamyltransferase or lactate dehydrogenase. In contrast to the other markers, gamma-glutamyltransferase activity was lower in fetal organs than in normal adult colon and colon tumors. These results are consistent with earlier observations that activities of these markers are significantly increased in the blood of patients with metastatic colon cancer.

Adult↗
PubMed1978

Controlling the highest lactate dehydrogenase activity known in nature.

In the shipjack, Euthynnus pelamis, white muscle appears to possess a powerful anaerobic capacity as well as a significant carbohydrate based aerobic potential. Lactate dehydrogenase occurs at higher activities than found thus far anywhere else in nature and clearly functions in anaerobic glycolysis. Alpha-glycerophosphate dehydrogenase also occurs in unusually high activities and appears to play a role in aerobic glycolysis. Regulation of these two reactions is accomplished by temperature, pH, and creatine phosphate levels. High temperature, low pH, and low creatine phosphate levels all appear to favor lactate dehydrogenase over alpha-glycerophosphate dehydrogenase; low temperature, high pH, and high creatine-phosphate levels, all expected during the quiescent state in this species, and when metabolism in aerobic, all favor alpha-glycerophosphate dehydrogenase activity.

Adenosine Triphosphate↗
PubMed1994

A lactate dehydrogenase (LDH)-based immunoassay for detection of cell surface antigens and its application to the study of MHC class I-binding peptides.

A lactate dehydrogenase (LDH)-based immunoassay, referred to as CPEIA (cell panning enzyme immunoassay), has been developed for the detection of cell-surface antigens. CPEIA is similar to a panning assay, in that it is based on the capture of cells bearing an antigen of interest by means of an antibody immobilized to a 96-well microtiter plate. Attachment of the cells is then measured by addition of a substrate for the intracellular enzyme lactate dehydrogenase. The substrate solution also contains the nonionic detergent Triton X-100 to lyse the cells and release LDH, which converts the substrate p-iodonitrotetrazolium violet (INT) from yellow to red. The intensity of the color resulting from the LDH-catalyzed reaction is proportional to the number of cells bound to the plate. The procedure does not require fixation of the cells, centrifugation, and blocking steps, resulting in a more convenient assay. CPEIA has been used for the detection of MHC class I antigens and other molecules on the surfaces of mouse cell lines and concanavalin A (ConA)-stimulated T lymphocytes. In addition, the assay has been used to detect peptide binding to Db and Kb MHC class I molecules on the surface of the mutant cell line RMA-S. The half-maximal responses for peptide-MHC class I interactions at different peptide concentrations can be determined with the assay, allowing the apparent dissociation constants to be calculated.

Amino Acid Sequence↗
PubMed1975

Biospecific affinity chromatography in aqueous-organic cosolvent mixtures. The effect of ethylene glycol on the binding of lactate dehydrogenase to an immobilised-AMP analogue.

The effect of the weak polarity-reducing agent, ethylene glycol, on the binding of pig heart lactate dehydrogenase to N6-(6-aminohexyl)-AMP-Sepharose has been investigated. In the absence of the reagent and under the conditions used, a non-specific interaction of the enzyme with the adsorbent led to recoveries of enzyme activity as low as 60% when the enzyme was eluted from the columns with a linear NADH gradient. The inclusion of low concentrations of ethylene glycol in column irrigants considerably improved the recovery of enzyme activity with quantitative recoveries being obtained in the presence of 20-30%. Concentrations of ethylene glycol about 35% altered the native conformation of lactate dehydrogenase and led to a decreased affinity for the immobilised ligand. Under these conditions, the altered protein fluorescence and decreased ability to bind NADH could be correlated with the chromatographic behaviour of the enzyme on columns of N6-(6-aminohexyl)-AMP-Sepharose. These effects were exploited to elute the enzyme from a column of immobilised-AMP with a linear gradient of ethylene glycol.

Adenosine Monophosphate↗
PubMed1984

Arylthallium(III) reagents for protein modification. Inhibition of lactate dehydrogenase from various sources by o-carboxyphenylthallium(III) bistrifluoroacetate.

The use of organothallium compounds for protein/macromolecule modification and as probes for n.m.r. and fluorescence is introduced. Lactate dehydrogenase from a number of species was rapidly and specifically inhibited by o-carboxyphenylthallium(III) bistrifluoroacetate and p-methylphenylthallium(III) bistrifluoroacetate. Inhibition of rabbit muscle lactate dehydrogenase by o-carboxyphenylthallium(III) bistrifluoroacetate was time-dependent and not reversible by gel filtration. A small degree of re-activation was possible by incubation with dithiothreitol. The time course of the inactivation kinetics showed two phases, only the first, and faster, of which was efficiently prevented by the presence of cofactor, NADH. Inhibition rates depended on the structure of the thallium reagent, its concentration and the temperature. No significant inhibition was found by thallous acetate or thallic trifluoroacetate. Saturation kinetics were observed for the inhibition by o-carboxyphenylthallium(III) bistrifluoroacetate of the pig heart enzyme. The possibilities of various cross-linking activities of these reagents are addressed. Mechanisms of the inhibition are discussed.

Animals↗
PubMed1995

Stopped-flow kinetic and biophysical studies of membrane-associated D-lactate dehydrogenase of Escherichia coli.

The enzyme kinetics of the FAD-containing membrane-associated D-lactate dehydrogenase (D-LDH) of Escherichia coli have been investigated by stopped-flow spectroscopy. The reduction of D-LDH by the substrate, D-lactate, exhibits a two-stage behavior as observed by the absorbance change for the enzyme-bound FAD. The fast stage with a maximum rate of 400 s-1 represents the rapid formation of the enzyme-substrate complex and the formation of the equilibrium between the oxidized and the reduced enzyme-substrate complexes. The slow stage, which occurs on the order of 0.36 s-1, represents the slow release of the product, pyruvate, from the reduced enzyme. The formation of a D-LDH semiquinone radical was not observed during the oxidation of D-lactate by D-LDH at 25 degrees C. However, during the subsequent electron transfer from the reduced enzyme to a nitroxide spin-label, a one-electron acceptor, an enzyme intermediate has been observed and identified by both optical and EPR spectroscopies as an anionic semiquinone. Results from 1H-NMR spectroscopic studies suggest the possible formation of a substrate carbanion when D-lactate is bound at the active site of D-LDH.

2,6-Dichloroindophenol↗
PubMed1992

Kinetic analysis of duck epsilon-crystallin with L-lactate dehydrogenase activity: determination of kinetic constants and comparison of substrate specificity.

A systematic analysis of the kinetic properties of duck lens epsilon-crystallin with lactate dehydrogenase [LDH, (E.C. 1.1.1.27)] activity was carried out by employing some 19 different alpha-keto acids as substrates for this NADH-dependent LDH-catalyzed reaction. The steady-state Michaelis and catalytic constants (Km, kcat) were determined for a broad range of organic compounds. The results provide important insights regarding the binding and affinity of substrates to active sites of this enzyme crystallin and indicate a great potential for the application of the stable epsilon-crystallin as a catalyst to the synthesis of some important chiral alpha-hydroxyacids in a convenient and efficient way. It is also demonstrated for the first time that in addition to the enzymatic activity of lactate dehydrogenase, duck epsilon-crystallin also possesses the enzymatic activity of malate dehydrogenase.

Animals↗
PubMed1971

Nicotinamide adenine dinucleotide-dependent and nicotinamide adenine dinucleotide-independent lactate dehydrogenases in homofermentative and heterofermentative lactic acid bacteria.

Three homofermentative (Lactobacillus plantarum B38, L. plantarum B33, Pediococcus pentosaceus B30) and three heterofermentative (Leuconostoc mesenteroides 39, L. oenos B70, Lactobacillus brevis) lactic acid bacteria were examined for the presence or absence of nicotinamide adenine dinucleotide (NAD)-dependent and NAD-independent d- and l-lactate dehydrogenases. Two of the six strains investigated, P. pentosaceus and L. oenos, did not exhibit an NAD-independent enzyme activity capable of reducing dichlorophenol indophenol. The pH optima of the lactic dehydrogenases were determined. The NAD-dependent enzymes from homofermentative strains exhibited optima at pH 7.8 to 8.8, whereas values from 9.0 to 10.0 were noted for these enzymes from heterofermentative organisms. The optima for the NAD-independent enzymes were between 5.8 and 6.6. The apparent Michaelis-Menten constants determined for both NAD and the substrates demonstrated the existence of a greater affinity for d- than l-lactic acid. A comparison of the specific NAD-dependent and NAD-independent lactate dehydrogenase activities revealed a direct correlation of the d/l ratios of these activities with the type of lactic acid produced during the growth of the organism.

Ammonium Sulfate↗
PubMed1999

Affinity isolation of a cold-adapted enzyme: lactate dehydrogenase from Bacillus psychrosaccharolyticus.

A simple, economical and rapid affinity chromatography procedure with dyes as the ligand has been described for the one-step purification of a cold-adapted lactate dehydrogenase. Non-specific elution of Procion blue H-ERD-modified Sepharose yielded homogeneous preparations of lactate dehydrogenase both in column based procedures and in batch wise operations. Low operational temperatures resulted in the enhanced binding of the enzyme to the blue dye. The dissociation constants of the enzyme-dye complexes were 7.2 +/- 0.2 microM and 11.2 +/- 0.2 microM at 5 degrees C and 20 degrees C respectively.

Bacillus↗
PubMed2005

Structure of lactate dehydrogenase from Plasmodium vivax: complexes with NADH and APADH.

Malaria caused by Plasmodium vivax is a major cause of global morbidity and, in rare cases, mortality. Lactate dehydrogenase is an essential Plasmodium protein and, therefore, a potential antimalarial drug target. Ideally, drugs directed against this target would be effective against both major species of Plasmodium, P. falciparum and P. vivax. In this study, the crystal structure of the lactate dehydrogenase protein from P. vivax has been solved and is compared to the equivalent structure from the P. falciparum enzyme. The active sites and cofactor binding pockets of both enzymes are found to be highly similar and differentiate these enzymes from their human counterparts. These structures suggest effective inhibition of both enzymes should be readily achievable with a common inhibitor. The crystal structures of both enzymes have also been solved in complex with the synthetic cofactor APADH. The unusual cofactor binding site in these Plasmodium enzymes is found to readily accommodate both NADH and APADH, explaining why the Plasmodium enzymes retain enzymatic activity in the presence of this synthetic cofactor.

Animals↗
PubMed1992

Primary structure, physicochemical properties, and chemical modification of NAD(+)-dependent D-lactate dehydrogenase. Evidence for the presence of Arg-235, His-303, Tyr-101, and Trp-19 at or near the active site.

The NAD(+)-dependent D-lactate dehydrogenase was purified to apparent homogeneity from Lactobacillus bulgaricus and its complete amino acid sequence determined. Two gaps in the polypeptide chain (10 residues) were filled by the deduced amino acid sequence of the polymerase chain reaction amplified D-lactate dehydrogenase gene sequence. The enzyme is a dimer of identical subunits (specific activity 2800 +/- 100 units/min at 25 degrees C). Each subunit contains 332 amino acid residues; the calculated subunit M(r) being 36,831. Isoelectric focusing showed at least four protein bands between pH 4.0 and 4.7; the subunit M(r) of each subform is 36,000. The pH dependence of the kinetic parameters, Km, Vm, and kcat/Km, suggested an enzymic residue with a pKa value of about 7 to be involved in substrate binding as well as in the catalytic mechanism. Treatment of the enzyme with group-specific reagents 2,3-butanedione, diethylpyrocarbonate, tetranitromethane, or N-bromosuccinimide resulted in complete loss of enzyme activity. In each case, inactivation followed pseudo first-order kinetics. Inclusion of pyruvate and/or NADH reduced the inactivation rates manyfold, indicating the presence of arginine, histidine, tyrosine, and tryptophan residues at or near the active site. Spectral properties of chemically modified enzymes and analysis of kinetics of inactivation showed that the loss of enzyme activity was due to modification of a single arginine, histidine, tryptophan, or tyrosine residue. Peptide mapping in conjunction with peptide purification and amino acid sequence determination showed that Arg-235, His-303, Tyr-101, and Trp-19 were the sites of chemical modification. Arg-235 and His-303 are involved in the binding of 2-oxo acid substrate whereas other residues are involved in binding of the cofactor.

Amino Acid Sequence↗
PubMed1978

[Lactate dehydrogenase and Krebs cycle enzyme activity in rat liver during the growth of transplanted and spontaneous tumors].

Certain distinctions in the mouse and rat liver responses to transplanted and spontaneous tumours have been discovered at the initial periods of their growth. The most pronounced changes (the mosaic distribution of enzymatic activity in the lobe) are observed in the case of spontaneous tumours. Activities the Krebs cycle enzymes, especially of NAD-dependent enzymes are seen inhibited in the tumour-bearing liver at the terminal periods of growth of both spontaneous and transplanted tumours; lactate dehydrogenase activity increases (with the exception of mitochondrial lactate dehydrogenase in the rat liver with transplanted sarcomas).

Aconitate Hydratase↗
PubMed2001

Intrinsic versus extrinsic stabilization of enzymes: the interaction of solutes and temperature on A4-lactate dehydrogenase orthologs from warm-adapted and cold-adapted marine fishes.

We examined the effects of temperature and stabilizing solutes on A4-lactate dehydrogenase (A4-LDH) from warm- and cold-adapted fishes, to determine how extrinsic stabilizers affect orthologs with different intrinsic stabilities. Conformational changes during substrate binding are rate-limiting for A4-LDH, thus stabilization due to intrinsic or extrinsic factors leads to decreased activity. A4-LDH from a warm-temperate goby (Gillichthys mirabilis), which has lower values for kcat and the Michaelis constant for pyruvate ( K m PYR), was intrinsically more stable than the orthologs of the cold-adapted Antarctic notothenioids Parachaenichthys charcoti and Chionodraco rastrospinosus, as shown by a higher apparent transition ('melting') temperature (Tm(APP)). We used four solutes, glycerol, sucrose, trimethylamine-N-oxide and poly(ethylene glycol) 8000, which stabilize proteins through different modes of preferential exclusion, to study temperature-solute interactions of the three orthologs. Changes in Tm(APP) were similar for all orthologs in each solute tested, but the catalytic rate of G. mirabilis A4-LDH was decreased most by solutes and increased most by temperature. In contrast, the K m PYR values of the Antarctic orthologs were more affected than that of the goby by both solutes and temperature. We conclude that (a) preferential exclusion of solutes functions within the native state of A4-LDH to favor conformational microstates with minimal surface area; (b) the varied effects of the different solutes on the kinetic properties are due to the interaction between this nonspecific stabilization and the differing intrinsic stabilities of the orthologs; (c) the catalytic rates of A4-LDH orthologs are equally affected by stabilizing solutes, if measurements are made at physiologically appropriate temperatures; and (d) global stability and localized flexibility of these A4-LDH orthologs may evolve independently.

Animals↗