PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “LACTATE DEHYDROGENASE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 253 records · Page 14Linked to original sources
PubMed2006

Lactate production yield from engineered yeasts is dependent from the host background, the lactate dehydrogenase source and the lactate export.

BACKGROUND: Metabolic pathway manipulation for improving the properties and the productivity of microorganisms is becoming a well established concept. For the production of important metabolites, but also for a better understanding of the fundamentals of cell biology, detailed studies are required. In this work we analysed the lactate production from metabolic engineered Saccharomyces cerevisiae cells expressing a heterologous lactate dehydrogenase (LDH) gene. The LDH gene expression in a budding yeast cell introduces a novel and alternative pathway for the NAD+ regeneration, allowing a direct reduction of the intracellular pyruvate to lactate, leading to a simultaneous accumulation of lactate and ethanol. RESULTS: Four different S. cerevisiae strains were transformed with six different wild type and one mutagenised LDH genes, in combination or not with the over-expression of a lactate transporter. The resulting yield values (grams of lactate produced per grams of glucose consumed) varied from as low as 0,0008 to as high as 0.52 g g-1. In this respect, and to the best of our knowledge, higher redirections of the glycolysis flux have never been obtained before without any disruption and/or limitation of the competing biochemical pathways. CONCLUSION: In the present work it is shown that the redirection of the pathway towards the lactate production can be strongly modulated by the genetic background of the host cell, by the source of the heterologous Ldh enzyme, by improving its biochemical properties as well as by modulating the export of lactate in the culture media.

Journal Article↗
PubMed1998

Homotropic activation via the subunit interaction and allosteric symmetry revealed on analysis of hybrid enzymes of L-lactate dehydrogenase.

L-Lactate dehydrogenase from Bifidobacterium longum shows homotropic activation by pyruvate as well as heterotropic activation by fructose 1,6-bisphosphate. Hybrid enzymes were produced from the wild-type subunit and a mutant subunit, whose substrate specificity was altered to that of malate dehydrogenase, and separated to analyze the substrate-induced homotropic activation mechanism. Oxamate, a competitive inhibitor of L-lactate dehydrogenase, was used to mimic the substrate-induced activation of the wild-type subunit as "a regulatory subunit." The malate dehydrogenase activity of the mutant subunit as "the catalytic subunit" of the hybrid enzymes was measured, and the activity of the mutant subunit was activated on the addition of oxamate. Thus, we directly observed the inter-subunit homotropic activation transmitted from the wild-type to the mutant subunit. Moreover, "isomeric" hybrid enzymes that have different structural subunit arrangements but identical subunit compositions showed identical kinetic natures. This indicates that the enzyme maintains its subunit symmetry during the allosteric transition.

Bifidobacterium↗
PubMed1981

Effects of halides on reduced nicotinamide adenine dinucleotide binding properties and catalytic activity of beef heart lactate dehydrogenase.

Beef heart lactate dehydrogenase has anion binding sites with selective affinities for fluoride and chloride. Fluoride competitively inhibits the catalytic activity of the enzyme and appears in a ternary enzyme-reduced nicotinamide adenine dinucleotide (NADH)-fluoride complex detectable in fluorescence and circular dichroism measurements. The presence of fluoride augments NADH binding, with a free energy of stabilization of -0.8 kcal/mol. NADH and chloride are strongly antagonistic, in fact, almost mutually exclusive or competitive, in their interaction with beef heart lactate dehydrogenase. In addition, the Hill coefficient for NADH binding undergoes a small but repeatable decline, reaching a minimum value of 0.75-0.8 at physiological NaCl concentrations. Dilution experiments showed that NADH binding in the presence of NaCl is independent of enzyme concentration, demonstrating that the chloride sensitivity is not linked to reversible dissociation of the enzyme. The NADH binding equilibria determined in NaCl, KCl, or CsCl are identical. The minimal effects of chloride on the fluorescence and circular dichroism spectra of the bound NADH suggest that it binds primarily at sites other than the one occupied by fluoride.

Animals↗
PubMed1982

Serum lactate dehydrogenase and its isoenzymes in men with maldescended testes.

Serum lactate dehydrogenase and lactate dehydrogenase isoenzymes were determined as a screen for testicular germ cell neoplasia in 130 men with maldescended testes. A testicular tumor was found on clinical examination in 1 patient, which was revealed to be embryonal carcinoma, teratoma, yolk sac tumor and carcinoma in situ on orchiectomy. Subclinical testicular germ cell neoplasia was found on testicular biopsy in 3 men (1 with microinvasive seminoma and 2 with carcinoma in situ). These 4 patients had normal serum lactate dehydrogenase and serum lactate dehydrogenase isoenzymes. Elevated serum lactate dehydrogenase was noted in 3 men without testicular germ cell neoplasia: 1 had predominantly increased serum lactate dehydrogenase isoenzymes 1 to 3 and 2 had slightly increased serum lactate dehydrogenase isoenzymes 3 and 4. Serum lactate dehydrogenase and lactate dehydrogenase isoenzymes were not sensitive to detect testicular germ cell tumors in a subclinical stage.

Cryptorchidism↗
PubMed1976

Spectrophotometric and electrochemical determinations of L(+)-lactate in blood by use of lactate dehydrogenase from yeast.

Lactate can be determined rapidly in blood by spectrophotometric and amperometric (enzyme electrode) procedures based on its oxidation by ferricyanide, the reaction being catalyzed with yeast L(+)-lactate dehydrogenase (cytochrome b2) (EC 1.1.2.3). In the photometric method lactate can be measured in a few minutes, but blood samples must first be deproteinized. In the amperometric procedure no treatment of blood is needed except ferricyanide addition. The enzyme electrode we used has a response time shorter than 1 min when its critical variables are optimized. Preliminary standardization is reduced to minimum operation, because electrode response is proportional to lactate concentration over a wide range (0.1 to 8.0 mol/liter) and many determinations can be done with little cost in enzyme. A simple electrical device ("two-electrode device") is described that is well suited for furture micro-cell construction. Lactate determinations on a series of normal blood samples show no deviation between results by these new methods and the usual ultraviolet spectrophotometric lactate tests.

Animals↗
PubMed1984

The relationship between gastric carcinoma and gastric juice lactate (L + D) and lactate dehydrogenase.

L-Lactate, D-lactate, and lactate dehydrogenase (LDH) levels were measured in the resting gastric juice of 73 patients and mean levels were found to be significantly higher in patients with gastric carcinoma than in those with benign gastric ulcer or those with normal stomachs. Raised levels of gastric juice L-lactate (greater than 1.3 mmol/l), D-lactate (greater than 0.15 mmol/l), and LDH (greater than 55 IU/1) were seen in 14 of 27 patients with carcinomas, two of 15 with benign ulcers, and six of 31 controls. Both L/D-lactate and LDH levels correlated with tumor size and depth of invasion. While six problem cases with large gastric lesions were correctly diagnosed using these indices, there was only poor sensitivity and moderate specificity, as early cancers had normal L/D-lactate and LDH levels, and these indices were raised in a significant number of controls. Thus while it is of interest that L/D-lactate and LDH are elevated in the gastric juice of patients with gastric carcinoma there appears to be little optimism for using these indices in the early diagnosis of gastric neoplasia.

Adult↗
PubMedDate not supplied

[Lactate level in the tissues of animals with a tumor administered oxythiamine and the properties of lactate dehydrogenase].

Content of lactate in blood, liver and kidney tissues, skeletal muscle and in tumor tissue as well as some properties of lactate dehydrogenase (LDH), isolated from liver tissue, were studied in three groups of rats - intact rats, the tumor-bearing animals with sarcoma S-45 and the tumor-bearing rats treated with hydroxythiamin within 22 days. In skeletal muscle on the side of the tumor localization content of lactate was decreased as compared with the opposite side of the body. As shown by analysis of correlation between the content of lactate and the tumor weight and the lactate concentration in the tumor-bearing rat tissues studied, the tumor appears to be responsible for consumption but not for production of lactate. Hydroxythiamin altered distinctly the ratio of lactate content in various tissues and normalized the liver tissue LDH isoenzyme spectrum in tumor-bearing rats; the vitamin decreased 9- and 15-fold the enzyme specific activity in oxidation of lactate in presence of NAD+ and NADP, respectively. After the hydroxythiamin treatment the apparent KM value of the enzyme, isolated from the tumor-bearing rat liver tissue, was increased with pyruvate and decreased with lactate as substrate.

Animals↗
PubMed1983

A cancer-associated lactate dehydrogenase is expressed in normal retina.

An unusual isozyme of lactate dehydrogenase, lactate dehydrogenase k, is found in high concentrations in cultured cells transformed by the Kirsten murine sarcoma virus and in many human cancer tissues. In experiments described here high levels of a lactate dehydrogenase k activity were detected in extracts of normal rodent retina. This activity had the same key properties as the human tumor isozyme, namely, a highly cathodic electrophoretic mobility and inhibition of enzymatic activity by oxygen and 5',5'-dipurinenucleoside tetraphosphates. Expression of this activity in the retina may be related to the high aerobic glycolysis characteristic of the retina, a metabolic feature shared with many tumors.

Animals↗
PubMedDate not supplied

S100 beta is a more reliable tumor marker in peripheral blood for patients with newly occurred melanoma metastases compared with MIA, albumin and lactate-dehydrogenase.

Lactate-dehydroxynase (LDH) has been described as a leading blood parameter in patients with melanoma metastases. However, recent data indicates that levels of S100 as well as melanoma inhibiting activity (MIA) in peripheral blood, correlate with melanoma progression. The aim of this study was to evaluate tumor markers S100, MIA, LDH and albumin in peripheral blood of 373 melanoma patients. 284 patients presented with in-situ or UICC stage I/II, and 89 with stage III/IV (54 tumor-free, 29 with newly occurred metastases). For newly occurred metastases, sensitivity was highest for S100 in peripheral blood (0.86), followed by MIA (0.80), LDH (0.48), and albumin (0.15). Specificity for albumin (0.99) and LDH (0.98) was higher than for S100 (0.91) and MIA (0.62). This data indicate that S100 in peripheral blood as compared to MIA, LDH and albumin appears to be the most appropriate tumor marker for newly occurred melanoma metastases.

Albumins↗
PubMed1997

Diagnostic value of lactate dehydrogenase isoenzyme pattern in pleural effusions.

Lactate dehydrogenase isoenzymes have been used to classify the nature of pleural effusion. Nevertheless, studies have reported conflicting results. The objective of this study was to evaluate the diagnostic value of lactate dehydrogenase isoenzymes in the analysis of pleural effusions. Pleural fluid samples obtained from three respective diagnostic groups: group I transudate (n = 23), group II parapneumonic effusion (n = 29) and group III malignant effusion or pleuritis carcinomatosa (n = 41) were evaluated. Total lactate dehydrogenase activity and lactate dehydrogenase (LDH) isoenzyme pattern were significantly different between transudative (group I) and exudative (group II and III) effusions. Group II and III showed a low percentage of LDH1 (p < 0.001), whereas the percentages of LDH4 (p < 0.001) and LDH5 (p < 0.001) were higher compared to group I. Moreover, in exudative effusions the percentage of LDH1 (p < 0.005), LDH4 (p < 0.005), as well as LDH5 (p < 0.005) were significantly different between parapneumonic and malignant effusions. In contrast to relative lactate dehydrogenase isoenzyme values, the absolute values of lactate dehydrogenase isoenzymes did not differ between group II and group III. Logistic regression analysis yielded a strong discrimination between group I and II+III, simultaneously using lactate dehydrogenase, glucose and protein as explanatory variables. Logistic regression analysis yielded only a weak discrimination between group II and III, simultaneously using lactate dehydrogenase, glucose and the absolute values of LDH2 and LDH4 as explanatory variables. In conclusion, the lactate dehydrogenase isoenzyme pattern differed between pleural effusions of transudative and exudative origin. However, including lactate dehydrogenase isoenzyme activities in the biochemical work-up of pleural effusions did not reveal an additional discriminatory value in the assessment of the classification of these effusions.

Aged↗
PubMed1986

Evaluation of localization and intensity of the reactions of succinic dehydrogenase, NADH tetrazole reductase, and lactate dehydrogenase in developing rat testis. II: After cadmium chloride treatment.

The described experiments showed the influence of a single dose of cadmium chloride (1.5 mg CdCl2/kg body mass) applied intraperitoneally on the activity of succinic dehydrogenase (SDH), NADH tetrazole reductase (NADH-R), and lactate dehydrogenase (LDH) in the rat's male gonad. It was ascertained that disturbances of the reaction begin to occur in the 7th d of post-fetal life: they increase gradually, first at the circumference and then the centre of the organ reaching their maximum in 1.5 year old rats.

Animals↗
PubMed1986

Evaluation of localization and intensity of the reactions of succinic dehydrogenase, NADH tetrazole reductase and lactate dehydrogenase in developing rat testis. I. Physiological conditions.

The localization, intensity, and character of the enzymatic reactions of the following enzymes responsible for the oxygenic and nonoxygenic respiration were under examination: succinic dehydrogenase (SDH), NADH tetrazole reductase (NADH-R), and lactate dehydrogenase (LDH). The features of the enzymatic reactions enumerated above were tested in male gonads of the rats on their 1st, 4th, 7th, 15th, 30th, 45th, 60th, 90th d and 1.5 year of post-fetal life. It was estimated on the examined reactions that their metabolic maturity in the gonad was reached on the 45th d of the rat's life.

Aging↗
PubMedDate not supplied

Effect of selected alcohol dehydrogenase inhibitors on human hepatic lactate dehydrogenase activity - an in vitro study.

Metabolic acidosis severely complicates methanol and ethylene glycol intoxications. Acidosis is caused by acid metabolites and can be intensified by lactate elevation. Lactate concentration depends on the NADH(2)/NAD ratio. Lactate dehydrogenase (LDH, E.C.1.1.1.27.) supplies more lactate when the level of NADH(2) is elevated. The aim of the study was to evaluate the effect of alcohol dehydrogenase (ADH) inhibitors and substrates: cimetidine, EDTA, 4-methylpyrazole (4-MP), Ukrain and ethanol on LDH activity. The activity of LDH was determined spectrophotometrically in human liver homogenates incubated with cimetidine, EDTA, 4-MP and Ukrain at concentrations of 2 x 10(-6), 10(-5) and 5 x 10(-5) m as well as ethanol at concentrations of 12.50, 25.00, 50.00 mm. The LDH activity was significantly increased by 10(-5) and 5 x 10(-5) m concentrations of cimetidine and 4-MP, and by all concentrations of ethanol. The most effective change of LDH activity of about 26% (P<0.01) was observed at the highest concentration of ethanol. Ukrain inhibited LDH activity at both concentrations, i.e. 10(-5) and 5 x 10(-5) m (P<0.05). However, EDTA did not significantly influence LDH activity. The data showed that ethanol and 4-MP, the main antidotes in methanol or ethylene glycol poisoning, may increase liver LDH activity - an undesirable effect during the therapy of patients intoxicated with these alcohols. On the other hand, the decrease of LDH activity in the presence of Ukrain is a promising finding but definitely requires further investigation.

Alcohol Dehydrogenase↗
PubMed1976

[Expression of the paternal genes for lactate dehydrogenase, glutamate dehydrogenase and acetylcholinesterase in the development of hybrid fish between species from the families of Cobitidae and Cyprinidae].

The time of expression of the paternal genes of glutamate dehydrogenase (GDH), lactate dehydrogenase (LDH) and acetylcholine esterase (AChE) was investigated in the development of fish hybrids. The species which differed by the thermostability of homologous enzymes were selected as parental pairs. The appearance of differences in the thermostability of homologous enzymes between the hybrids and the maternal species suggested the beginning of paternal enzyme synthesis in the hybrid embryos. Differences in the AChE thermostability appeared simultaneously with the enzyme activity at the stage of first muscle contractions (35 hrs of development), differences in the mitochondrial GDH thermostability appeared at the stage of hatching (50-60 hrs) and those in the LDH thermostability 12-17 days after hatching. The total activity of AChE and GDH sharply increased during the period of the paternal enzyme appearance whereas the activity of LDH suffered practically no changes. Differences in the AChE thermostability between the hybrids and the maternal species are the same for both the total AChE (in supernatant, 15,000 gX10 min.) and the solubilised AChE (in supernatant, 130,000 gX60 min.). AChE of the parental species and the hybrids have the same electrophoretic mobility. The differences in the thermostability of enzymes are preserved following the electrophoresis in polyacrilamide gel.

Acetylcholinesterase↗
PubMed1981

Comparison of procedures for the measurement of the anodal isoenzymes of lactate dehydrogenase in serum.

Lactate dehydrogenase (LD) isoenzyme-1 levels (LD1) determined after immunoprecipitation of M-subunits, LD1 activity by electrophoresis, and the activities of alpha-hydroxybutyrate dehydrogenase (HBD), urea-stable LD, and heat-stable LD, by Association of Clinical Biochemists Proposed Methods, were examined for their ability to differentiate between serum samples from patients with cardiac or liver disease. Compared with total LD, all methods gave higher serum activity in patients with cardiac disease than in those with liver disease. Differentiation between patient groups was greatest for LD1 by immunoprecipitation, followed by heat-stable LD and LD1 by electrophoresis. HBD and urea-stable LD both gave less discrimination, with negligible difference between these two procedures. LD1 activity by immunoprecipitation correlated well with LD1 activity determined by isoenzyme electrophoresis with densitometric scanning. The advantages and disadvantages of the various procedures are considered.

Drug Stability↗