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 703 records · Page 39Linked to original sources
PubMed1978

Affinity chromatography of bacterial lactate dehydrogenases.

The affinity system used was the immobilized oxamate derivative previously used to purify mammalian lactate dehydrogenases. The bacterial dehydrogenases specific for the L-stereoisomer of lactate behaved in the same way as the mammalian enzymes, binding strongly in the presence of NADH. The D-lactate-specific enzymes, however, did not show any biospecific affinity for this gel. The L-specific enzymes could be purified to homogeneity in one affinity-chromatographic step. The D-specific enzymes could be efficiently separated from the L-specific ones and could then be further purified on an immobilized NAD derivative. The mechanism of activation of the lactate dehydrogenase from Streptococcus faecalis by fructose 1,6-bisphosphate was investigated by using the immobilized oxamate gel.

Bacteria↗
PubMed1984

Automated kinetic assay for lactate dehydrogenase isoenzyme 1 by centrifugal analysis after alkaline inactivation.

Lactate dehydrogenase isoenzyme 1 (LD1, EC 1.1.1.27) has been used widely as a marker for myocardial infarction, and many analytical methods for it have been developed, most of which are relatively labor intensive. On the basis of a recent report by Takizawa et al. (Clin Chem 29: 1941-1945, 1983) describing the marked stability of LD1 in buffered alkaline solutions, and with use of a centrifugal analyzer, we have developed a fully automated assay for LD1. Results with this method are precise (between-day SD = 2.1 U/L), vary linearly with LD1 activity to 600 U/L, and correlate well with LD1 as determined by immunological (Roche Isomune-LD) and agarose electrophoretic methods (r = 0.985 and 0.986, respectively). Furthermore, the method is easy and convenient, and should provide a substantial savings in labor and reagent costs to laboratories currently determining LD1 by electrophoretic or immunologic methods.

Autoanalysis↗
PubMed1965

Lactate dehydrogenase Isozymes: substrate inhibition in various human tissues.

The total lactate dehydrogenase (LDH) in whole homogenates of various human tissues reacts more similarly toward pyruvate and lactate at 25 degrees C than expected from the marked differences in substrate inhibition at this temperature between isolated, purified LDH-1, and LDH-5. At 37 degrees C, LDH-5 closely resembles LDH-1 in extent of inhibition by substrate. These results are incompatible with the theory that differences in degree of isozyme inhibition by substrate have resulted in predominance of LDH-5 in aerobic tissues and predominance of LDH-1 in aerobic tissues.

Chemical Phenomena↗
PubMed1985

Modification of the kinetic parameters of chicken liver cytoplasmic aspartate aminotransferase by lactate dehydrogenase.

A method for the purification of chicken liver soluble aspartate aminotransferase, lactate dehydrogenase free, is proposed. The preparation, which contained a mixture of the five molecular forms of the enzyme, showed a 120-fold increase in specific activity, with respect to the initial homogenates. Differences in Km(2-oxoglutarate) and saturating concentrations among solutions of purified enzyme and soluble fraction were due to the 2-oxoglutarate reductase activity of lactate dehydrogenase.

Animals↗
PubMed1975

Enzymes of normal and malignant trophoblast: phosphoglucose isomerase, phosphoglucomutase, hexokinase, lactate dehydrogenase, and alkaline phosphatase.

In this study we compare the specific activities and isoenzyme patterns of five enzymes--phosphoglucose isomerase, phosphoglucomutase, hexokinase, lactate dehydrogenase, and alkaline phosphatase--in term placenta with the analogous enzymes in a clone of choriocarcinoma cells grown in culture. Phosphoglucose isomerase, phosphoglucomutase, and lactate dehydrogenase specific activities of the choriocarcinoma did not differ by more than two or three times from the mean activities of the comparable enzymes in placenta; the specific activity of hexokinase in the choriocarcinoma amounted to 14 per cent of the mean value for placenta. In contrast, the mean specific activity of heat-stable alkaline phosphatase in the choriocarcinoma amounted to only 1 per cent of the mean value for placenta. By growing the cells in 5-bromodeoxyuridine, 20 mug per milliliter, we were able to increase alkaline phosphatase activity to 68 per cent of the mean value for placenta. For both extracts, phosphoglucose isomerase zymograms were similar and phosphoglucomutase zymograms were similar. The hexokinase zymogram of term placenta showed two isoenzymes which stained more intensely with 0.5 mM. glucose than with 0.1M glucose. A hexokinase isoenzyme was observed in zymograms of both extracts which stained more intensely with 0.1M glucose than with 0.5 mM glucose. Lactate dehydrogenase exhibited an extra isoenzyme in the choriocarcinoma extract. When the cells were cultivated in medium containing 5 mug per milliliter of 5-bromodeoxyuridine, the induced phosphatase in the cell line was electrophoretically similar to placental phosphatase. At higher concentrations of 5-bromodeoxyuridine, the most anodal isoenzyme was 0.5 cm. slower in mobility than the comparable placental isoenzyme.

Alkaline Phosphatase↗
PubMed1994

Neisseria gonorrhoeae possesses two nicotinamide adenine dinucleotide-independent lactate dehydrogenases.

An important metabolic capability of Neisseria gonorrhoeae is the utilization of host-derived lactate. Two isoenzymes of the membrane-associated, pyridine dinucleotide-independent type of lactate dehydrogenase (iLDH) participate in lactate assimilation, but exhibit distinctive properties. Isoenzyme iLDH-I utilized lactate exclusively as substrate, exhibiting a preference for the D-isomer. In contrast, isoenzyme iLDH-II exhibited broad substrate specificity (lactate, phenyllactate, and 4-hydroxyphenyllactate), but was stereospecific for the L-isomers. These results explain the difficulty in isolating mutants unable to utilize lactate.

Cell Membrane↗
PubMed1976

The separation of partially modified lactate dehydrogenase by affinity chromatography. The specific activity of protomers?

Pig heart lactate dehydrogenase (L-lactate: NAD+ oxidoreductase, EC 1.1.1.27) was partially inactivated by reaction with phenylmaleimide. The resulting protein mixture was separated by affinity chromatography on a Sepharose-linked oxamate column yielding three distinct enzyme fractions with one, two and three out of four subunits being modified. The specific activities of these samples were lower than expected from the degree of modification, while the maximum binding capacity of NADH-oxamate related well to the number of catalytic centers modified. A possible cooperative effect in the native enzyme is discussed.

Animals↗
PubMed1979

Role of ions in the regulation of porcine lactate dehydrogenase.

Different ions affect the H4 and M4 isoenzymes of porcine lactate dehydrogenase (L-lactate: NAD+ oxidoreductase, EC 1.1.1.27) in the same way, inhibiting the enzyme at low pyruvate concentrations, whereas at high pyruvate concentrations, the activities were enhanced. The inhibition was competitive with regard to pyruvate and NADH. The enhancement of the enzyme activity at high pyruvate concentration is due to the increase in the Km value for pyruvate, implying that higher substrate concentrations are needed to obtain substrate inhibition. Sulphate behaved differently from the other ions. It inhibited in a noncompetitive manner with regard to pyruvate and did not activate the enzyme at high pryvuate concentration. The effect of ions increased with the size of the anion. The ionic strength was of less importance.

Animals↗
PubMed2005

[Comparative analysis at the nucleotide level of the genes encoding the lactate dehydrogenase enzyme of Plasmodium vivax and Plasmodium falciparum.].

In this study, the nucleotide sequence of the enzyme lactate dehydrogenase from Plasmodium vivax has been compared to the same enzyme from another malaria parasite Plasmodium falciparum. It was found that the identity between two sequences was 74.8%. The percentage of the GC value was found to be higher in the Plasmodium vivax lactate dehydrogenase (46.6%) than in that of Plasmodium falciparum (33%). The nucleotide sequence that corresponds to the 5 amino acid insertion in Plasmodium lactate dehydrogenase is also present in Plasmodium vivax. This site will be targeted in the design of novel antimalarials for Plasmodium vivax as has been for Plasmodium falciparum.

English Abstract↗
PubMed1980

Expression of lactate dehydrogenase isozyme X in haploid cells of pigeon testis.

Electrophoretic patterns of lactate dehydrogenase (EC 1.1.1.27) from adult testes show the existence of three different phenotypes for the isozyme X or C4 in populations of racing homer pigeons. These phenotypes are the expression of two different alleles at the Ldh c locus. Analysis of electrophoretic patterns of lactate dehydrogenase from lysates of mature spermatozoa isolated from pigeons heterozygous at the Ldh c locus indicates that the two different alleles are expressed in haploid cells. It is concluded that transcription of the gene coding for isozyme X must occur only in pre-meiotic cells.

Animals↗
PubMed1997

Modification of pyruvate kinase and lactate dehydrogenase in foot muscle of the sea mussel Mytilus galloprovincialis under anaerobiosis and recovery.

The modification of pyruvate kinase (PK) and lactate dehydrogenase (LDH) activity in foot muscle of the mussel Mytilus galloprovincialis during exposure to air and recovery in water was investigated. In the course of exposure to air, the activity of these enzymes measured at high and low substrate concentrations showed successive increases and decreases. Returning the mussels to water after exposure to air affected enzyme activity in a manner similar to anaerobiosis. When measuring at saturated concentrations of substrates and substrate and coenzyme for PK and LDH, respectively, the maximum activation of PK (37%) was observed at 4 h of animal exposure to air, and for LDH (67%) at 6 h exposure to air. During 24 h of exposure of animals to air, PK activity practically reached the stock level, while LDH was still activated (148%). The change in lactate dehydrogenase activity in mussel muscle during anoxia and recovery is described here for the first time. Variation in pyruvate kinase activity during exposure to air and recovery is linked to the alteration of half-maximal saturation constants and maximal velocity for both substrates. The possible role of reversible phosphorylation in the regulation of pyruvate kinase and lactate dehydrogenase properties is discussed.

Anaerobiosis↗
PubMedDate not supplied

Immobilization of lactate dehydrogenase on tetraethylorthosilicate-derived sol-gel films for application to lactate biosensor.

Tetraethylorthosilicate (TEOS)-derived sol-gel films were utilized for the immobilization of lactate dehydrogenase (LDH) by physical adsorption and sol-gel/LDH/sol-gel sandwich configuration. An attempt was made to ascertain the optimum pH and temperature for the immobilized LDH. It was shown that TEOS-derived sol-gel films containing physically adsorbed LDH exhibited linearity from 0.5 to 4 mM, whereas those containing LDH in sandwich configuration showed linearity from 0.5 to 3 mM L-lactate. These sol-gel films, immobilized with LDH, were found to be stable for about 4 weeks at 4-10 degrees C.

Adsorption↗
PubMed1988

Phosphorylation of lactate dehydrogenase by ATP.

Evidence is presented indicating that phosphorylation of porcine muscle lactate dehydrogenase by [gamma-32P] ATP occurs at carboxyl residues of the protein. The phosphoenzyme complex was moderately stable at pH 6.8 and 25 degrees C, with a half-life of 3.5 h. In the presence of NADH rapid dephosphorylation occurred. Formation of an abortive complex with NAD-pyruvate also caused hydrolysis of the phosphoenzyme. The phosphorylated lactate dehydrogenase was shown to serve as a phosphate donor for phosphorylation of ADP.

Adenosine Triphosphate↗
PubMed1984

L-Lactate dehydrogenase from Thermus caldophilus GK24, an extremely thermophilic bacterium. Desensitization to fructose 1,6-bisphosphate in the activated state by arginine-specific chemical modification and the N-terminal amino acid sequence.

Heat-stable and fructose-1,6-bisphosphate-activated L-lactate dehydrogenase (EC 1.1.1.27) has been purified from an extremely thermophilic bacterium, Thermus caldophilus GK24 [Taguchi, H., Yamashita, M., Matsuzawa, H. and Ohta, T. (1982) J. Biochem. (Tokyo) 91, 1343-1348]. N-terminal sequence analysis of the first 34 amino acids of the enzyme indicates that the N-terminal arm region (first 1-20 residues) known for the vertebrate L-lactate dehydrogenases is completely missing in the T. caldophilus enzyme, while there is a high homology of sequence between the regions which are considered to be part of the NAD-binding domain. The C-terminal amino acid of the enzyme was phenylalanine. Analysis of the amino acid composition showed that T. caldophilus enzyme contained much more arginine and fewer lysine than other bacterial and vertebrate L-lactate dehydrogenases. On modification reaction with 2,3-butanedione in the presence of NADH and oxamate, an enhanced activity of the T. caldophilus L-lactate dehydrogenase was obtained independently of fructose 1,6-bisphosphate, and the modified enzyme was desensitized to fructose 1,6-bisphosphate. Amino acid analysis indicated that such a desensitization in the active state was caused by the modification of only one arginine residue per the enzyme subunit. Desensitization of the enzyme was inhibited in the presence of fructose 1,6-bisphosphate. A similar desensitization was observed using 1,2-cyclohexanedione instead of 2,3-butanedione. The enzyme was irreversibly modified with 2,3-butanedione and characterized. The irreversibly modified enzyme also showed an enhanced activity independently of fructose 1,6-bisphosphate, and its pyruvate saturation curve was similar to that of the native enzyme measured in the presence of fructose 1,6-bisphosphate. Fructose 1,6-bisphosphate, which increases the thermostability of the native enzyme, did not affect that of the modified enzyme, while thermostability of the modified enzyme slightly decreased. Amino acid analysis indicated that only the arginine content was decreased by the modification. These results show that arginine residue(s) exist in the binding site for fructose 1,6-bisphosphate on the enzyme, and that the arginine residue(s) play some important role in the allosteric regulation of the enzyme activity.

Allosteric Regulation↗
PubMed1984

Purification and characterization of the lactate dehydrogenase (LDH-B4) allozymes of Fundulus heteroclitus.

In order to evaluate whether structural differences exist between allelic variants of a B-type lactate dehydrogenase (LDH; L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) in the minnow Fundulus heteroclitus, the allozymes (LDH-Ba4, LDH-Ba/Bb, and LDH-Bb4) were purified to homogeneity by affinity chromatography. Each variant was characterized as to holoenzyme and subunit molecular mass, isoelectric point (pI), thermal and urea stability, and susceptibility to proteolysis. Differences in electrophoretic mobilities were due to a lower pI for LDH-Ba4 (pI = 6.6) than for LDH-Bb4 (pI = 7.2). Stability to inactivation by heat, urea, and proteolysis was in each case: LDH-Bb4 greater than LDH-Ba/Bb greater than LDH-Ba4. Inactivation by trypsin may involve the arginine-rich catalytic loop of lactate dehydrogenase (50). The results suggest that the allozymes differ in their conformational flexibility.

Animals↗
PubMedDate not supplied

[Changes in subunit composition of lactate dehydrogenase at low temperatures].

Hybridization of M4- and H4-isoenzymes of lactate dehydrogenase in saline medium was studied during slow freezing down to -9.5; -23 and -30 degrees C. It is established that appearances of the enzyme hybrid forms is associated with free water freezing out and with an increase in the concentration of salts in the solution. No hybridization was observed under fast cooling of the enzyme down to -196 degrees C, under exposition in the concentrated solution of chloride and sodium phosphate without freezing and with freezing in deionized water. The mechanism of low-temperature hybridization of lactate dehydrogenase, based on concentration effects of salts which favour dissociation of a protein molecule into subunits, are under discussion. An assumption is advanced on an intensification of intermolecular interactions in liquid microphases of the frozen solution as a possible reason of the subunits recombination into hybrid isoenzymes.

Animals↗
PubMed1982

The use of subunit hybridization to monitor the reassociation of porcine lactate dehydrogenase after acid dissociation.

Reassociation of tetrameric porcine heart and skeletal muscle lactate dehydrogenases has been previously studied by cross-linking with glutaraldehyde (Bernhardt, G. et al. (1981) Z. Naturforsch. 36c, 772-777; Hermann, R. et al. (1981) Biochemistry 20, 5195-5201). Based on these data, the following kinetic model was proposed for the reconstitution of both isoenzymes: (nontranscribable formula, see text). In the present study, the kinetics of reassociation were determined from the changes of the hybrid patterns obtained upon the mixing of equal amounts of reassociating heart and skeletal muscle lactate dehydrogenases. For a quantitative interpretation of the kinetic data, the dependence of hybrid formation on the conditions of reconstitution was taken into account. Approximately binomial hybrid formation was observed only in a very narrow range of experimental conditions: enzyme concentration greater than 2.7 micrograms/ml, subunit ratio 1:1, temperature range 20-30 degrees C. At a total subunit concentration of 3.4 micrograms/ml (approximately 0.1 micrometers), the reassociation data determined by hybridization were found to be consistent with the proposed kinetic model.

Animals↗