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PubMed1980

Kinetic parameters of lactate dehydrogenases of some rumen bacterial species, the anaerobic ciliate Isotricha prostoma and mixed rumen microorganisms.

A number of kinetic parameters of the lactate dehydrogenases of three rumen bacterial species (Peptostreptococcus productus, Propionibacterium acnes and Actinomyces viscosus), the rumen ciliate Isotricha prostoma and mixed rumen microorganisms (MRM) with respect to NADH, pyruvate, fructose-1,6-diphosphate (FDP) as well as the effects of several nucleotide phosphates were studied. Partially purified LDH of Peptostr. productus had the same kinetic parameters as in crude cell free extracts. Values for Km, determined by Michaelis-Menten kinetics with pyruvate as the substrate, were in the same range for all lactate dehydrogenases. After feeding a cow, changes in the apparent Km and Vmax values for NADH of the total LDH activity in MRM were followed. It is suggested that of the factors studied the ratio NADH/NAD(H) and ATP are the most important regulatory factors for the lactate dehydrogenases of mixed rumen microorganisms.

Actinomyces↗

PubMed1977

Hepatitis B "e" antigen: an apparent association with lactate dehydrogenase isozyme-5.

Serums containing the "e" antigen of hepatitis B virus were subjected to electrophoresis in polyacrylamide gel. An extra band appeared in the lactate dehydrogenase isozyme pattern, but this band was undetectable in serums containing antibodies to the e antigenic determinant. Prior separation of the lactate dehydrogenase isozyme-5 fraction by chromatography of serum on minicolumns of diethylaminoethyl-Sephadex-A50 improved electrophoretic identification of the extra band. Neutralization with antibodies to the e antigen as well as by antibodies to the homologous d or y component of the hepatitis B surface antigen removed the extra band; antibodies to the lactate dehydrogenase isozyme-5 removed both the normal and the extra enzymatic band of isozyme-5. This feature of the e antigen provides an assay system for laboratory diagnosis of potential clinical usefulness and suggests its possible role in pathogenesis of hepatocellular injury.

Antibody Specificity↗

PubMedDate not supplied

[Lactate dehydrogenase in an interpolyelectrolyte complex. Function and stability].

A new method for encapsulating enzymes by multilayer polyelectrolyte coating is proposed. The method consists in a stepwise adsorption of polyelectrolytes from solution onto protein aggregates formed by salting out the proteins in highly concentrated salt solutions. Polystyrene sulfonate and fluorescence-labeled polyalylamine were used for capsule formation. The size of lactate dehydrogenase aggregates covered by four layer pairs of electrolytes was 1-5 microns, as indicated by fluorescence microscopy. The catalytic characteristics and stability of pig muscle lactate dehydrogenase (EC 1.1.1.13) incapsulated in multilayer electrolyte complex obtained by this method were studied. It was found that the affinity of the substrate pyruvate for the enzyme in the polyelectrolyte complex (K(M)) did not essentially change as compared with the free enzyme. Incapsulated lactate dehydrogenase showed the following features that distinguish it from the free form: (1) the lifetime in diluted solutions increases from 30 min (without capsules) to 1-2 days (in capsules); (2) a higher stability to basic denaturation (up to pH 10); and (3) the absence of substrate inhibition of enzyme in the polyelectrolyte complex. The changes in the catalytic characteristics of incapsulated lactate dehydrogenase are discussed in terms of an increase in effective pK values of amino acid perturbed by polyelectrolyte coating of enzyme.

Animals↗

PubMed1984

Developmental changes in lactate dehydrogenase and aldolase activity of the A2G-adr mouse with abnormal muscle function: further comparison with the 129Re-dy mutant.

Lactate dehydrogenase and aldolase activity were reduced in lateral gastrocnemius muscle from two mouse mutants, A2G-adr and 129Re-dy, with abnormal muscle function. The activities of both of these enzymes were significantly reduced in the lateral gastrocnemius muscle from the A2G-adr mice at ages varying from 2 weeks to 32 weeks, whereas the activities in the soleus, heart, liver, and brain were the same as in the control animals. The lactate dehydrogenase isoenzymes in the lateral gastrocnemius and soleus muscles from the A2G mice were quantified, and although those of the soleus were comparable in mutant and control muscle, the lateral gastrocnemius from the adr mutant had reduced activity of LDH 5 and increased activities of the other four isoenzymes. The findings suggest that the adr mutation is expressed in the white (Type II) muscle fibres and not in the red (Type I) fibres or in any of the organs studied. It is suggested that the initiation of differentiation into Type II fibres from the embryonic form is absent or delayed in the A2G mutant. The reduced activities of lactate dehydrogenase and aldolase in 129Re-dy muscle confirm the findings of other workers.

Aging↗

PubMed1985

Cloning studies on the gene coding for L-(+)-lactate dehydrogenase of Plasmodium falciparum.

We show that the L-(+)-lactate dehydrogenase (EC 1.1.1.27;L-lactate: NAD+-oxidoreductase) of Plasmodium falciparum (LDH-P) is encoded in the parasite genome. A monoclonal antibody (McAb 7.2) has been shown to bind the LDH-P subunit which has an apparent molecular mass of 35 kDa. A polyclonal antiserum raised against affinity purified LDH-P has been used to isolate cDNA clones containing LDH-P epitopes from a lambda gt11Tn5 expression library. DNA sequence analysis of one clone, lambda LDH-P.1, reveals a single open reading frame which shows a degree of homology to the N-terminal domain of known LDH amino acid sequences.

Amino Acid Sequence↗

PubMed1979

Endocytosis and breakdown of 125I-labelled lactate dehydrogenase isoenzyme M4 by rat liver and spleen in vivo.

1. Porcine lactate dehydrogenase isoenzyme M4 was labelled with 125I and injected intravenously into rats. Enzyme activity and radioactivity in plasma were cleared in an identical way with a half-life of about 30 min. This half-life was the same as that of unlabelled enzyme. 2. Uptake of label by liver and spleen was determined. Radioactivity in these tissues increased up to about 13 min after injection and subsequently declined. Radioautography indicated uptake of the enzyme by sinusoidal liver cells (probably Kupffer cells) and by spleen macrophages. After differential fractionation of liver, acid-precipitable radioactivity was largely found in the light mitochondrial and microsomal fractions, suggesting localization in lysosomes and endosomes respectively. 3. The amount of acid-soluble radioactive breakdown products in plasma started to rise between 7 and 15 min after injection. Breakdown in liver and spleen was retarded by previous injection of suramin, an inhibitor of lysosomal proteolysis. 4. The contribution of liver and spleen towards the clearance of the enzyme could be calculated from its half-life in plasma and its uptake by the organs within the first 13 min period after injection. Our results indicate that about 65% and 12% of the injected dose was taken up, and subsequently broken down, by liver and spleen respectively. 5. Unlabelled porcine lactate dehydrogenase isoenzyme H4 showed a plasma half-life of about 8 h. This isoenzyme is therefore endocytosed by liver at a much slower rate than isoenzyme M4 (if it is taken up at all).

Animals↗

PubMed2025

Lactate dehydrogenase a is a crucial biomarker that affects the prognosis, chemotherapy effect, and immune infiltration of breast cancer.

PURPOSE: Lactate dehydrogenase A (LDHA) is a key node in tumor growth, metabolism, and invasion and is upregulated across multiple cancers. However, the molecular mechanisms by which LDHA influences breast cancer (BC) remain unclear. We analyzed public datasets and an institutional cohort to clarify the relationship between LDHA and BC, with the aim of informing future therapeutic strategies. PATIENTS AND METHODS: Using The Cancer Genome Atlas (TCGA), we assessed LDHA expression in BC and examined its associations with tumor mutational burden (TMB), immune cell infiltration, immune checkpoint molecules, and drug sensitivity. We integrated multiple databases and used Kaplan-Meier analyses to evaluate prognostic value. To explore biological functions of LDHA, we performed Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). We then analyzed BC patients receiving neoadjuvant chemotherapy (NAC) at Harbin Medical University Cancer Hospital to test the relationship between serum lactate dehydrogenase (LDH) and pathological complete response (pCR). Finally, we used National Health and Nutrition Examination Survey (NHANES) data to examine the association between serum LDH and mortality. RESULTS: LDHA was upregulated in BC tissues, and higher expression was significantly associated with worse overall survival (OS), recurrence-free survival (RFS), and distant metastasis-free survival (DMFS). Functional analyses indicated enrichment of metabolic pathways, such as glycolysis. LDHA expression correlated with multiple immune cell populations, suggesting involvement in the tumor immune microenvironment. Lower LDHA expression was associated with greater sensitivity to several chemotherapeutic agents. In our institutional cohort, patients with lower serum LDH were more likely to achieve pCR, and LDH was an independent predictor of pCR. In NHANES, elevated serum LDH was linked to increased mortality risk. CONCLUSION: Our findings suggest that LDHA expression and serum LDH levels are promising prognostic biomarkers for survival and may predict chemotherapy response in BC patients. These results highlight the clinical relevance of LDHA-mediated metabolic pathways. However, as a correlational study, our findings warrant further validation through functional experiments to confirm LDHA's role as a potential therapeutic target.

Humans↗

PubMed1978

Pressure-adaptive differences in lactate dehydrogenases of congeneric fishes living at different depths.

The muscle-type (M4) lactate dehydrogenases of Sebastolobus altivelis, a deep-water scorpaenid, and S. alascanus, a shallower species, are electrophoretically indistinguishable, yet differ in pressure sensitivities. The lactate dehydrogenase of S. altivelis exhibits lower pressure sensitivities of substrate and coenzyme binding and catalytic rate. Such apparently pressure-adaptive kinetic properties may be important for establishing species depth zonation patterns in the ocean.

Adaptation, Biological↗

PubMed1994

Crystallization of D-lactate dehydrogenase from Lactobacillus bulgaricus.

The D-lactate dehydrogenase (D-LDH) from Lactobacillus bulgaricus has been purified and co-crystallized with its cofactor NAD+. Crystals suitable for X-ray diffraction experiments have been obtained from an ammonium sulfate solution by the hanging-drop method. The crystals belong to the orthorhombic space group C222 (or C222(1)) with cell dimensions a = 76.5 A, b = 93.3 A, c = 118.4 A and one monomer of 37,000 daltons per asymmetric unit. They diffract beyond 3.0 A resolution. Sequence comparison suggests that D-LDHs have no evolutionary relationship to L-LDHs and belong instead to the family of the D-2-hydroxyacid dehydrogenases. The X-ray crystallographic structure of the D-LDH from Lactobacillus bulgaricus will be a decisive test of this hypothesis.

Crystallization↗

PubMed1983

Amino acid sequence studies on lactate dehydrogenase C4 isozymes from mouse and rat testes.

Carboxymethylated sperm-specific lactate dehydrogenase isozyme C4 (LDH-C4) proteins from mouse and rat testes were cleaved with cyanogen bromide and trypsin. Proteins were also citraconylated and digested with trypsin. In the case of mouse LDH-C4 isozyme, all 7 CNBr and 11 limited tryptic (arginine) peptides were isolated and sequenced. Some of the CNBr peptides were further fragmented with trypsin and chymotrypsin and their compositions and/or sequences characterized. Also, 34 of the 36 expected tryptic peptides were purified, and their compositions and sequences determined. Amino acid sequences of these peptides purified from mouse LDH-C4 were overlapped into a complete covalent structure of the 330 residues. For rat LDH-C4, 5 of 6 expected CNBr peptides, 5 of 8 expected arginine peptides, and 28 of the 34 expected tryptic peptides were isolated, and their compositions and sequences were determined. Some of the CNBr and arginine peptides were further fragmented with chymotrypsin, thermolysin, or V8 protease, and their compositions and/or sequences characterized. The amino acid sequence of 85% of the 330 residues from rat LDH-C subunit has been unambiguously determined, and the sequences of the remaining regions were tentatively aligned on the basis of peptide compositions and sequence homologies with the other known lactate dehydrogenase sequences, including mouse LDH-C. A comparison of the proposed rat LDH-C sequence with the complete covalent structure of mouse LDH-C indicates that 27 differences are located in the established rat LDH-C sequence of 280 residues and that 5 additional differences are in the tentative sequence of the remaining 50 amino acids.

Amino Acid Sequence↗

PubMed1980

Lactate dehydrogenase isoenzyme patterns as a method of pregnancy detection in cattle.

The objective of this study was to evaluate serum lactate dehydrogenase isoenzyme patterns in open and pregnant Holstein and Hereford cows as a method of detecting pregnancy. Serum samples were collected from 26 Holstein and 13 Hereford cows and lactate dehydrogenase isoenzyme patterns were examined by electrophoresis and quantitated by scanning densitometry. Lactate dehydrogenase isoenzyme(4) and LDH(5) were found in higher concentration (P </= .05) in pregnant versus open Holstein cows. Twelve of 14 and 10 of 12 Holstein cows were correctly diagnosed as being pregnant and open, respectively by examining differences in serum concentrations of isoenzymes LDH(4) and LDH(5). Pregnancy was detected as early as 36 days of gestation. No differences were found in serum LDH isoenzyme patterns between pregnant and open Hereford cows. However, differences (P </= .05) in concentration of all five LDH isoenzymes were observed between Holstein and Hereford cows, which may lend insight into the metabolic significance of the elevation of LDH(4) and LDH(5) in pregnancy. The results suggest that elevation of serum LDH(4) and LDH(5) may be used as a means of pregnancy detection in the Holstein but not the Hereford cow.

Journal Article↗

PubMed1964

LACTATE DEHYDROGENASE IN PIGEON TESTES: GENETIC CONTROL BY THREE LOCI.

Homogenates of pigeon testes show three types of lactate dehydrogenase isozyme patterns. Recombination of the polypeptide subunits of the dehydrogenase in mixtures of the different types, and the distribution of the three isozyme patterns in six different pigeon populations demonstrated that lactate dehydrogenase synthesis in pigeon testes is under the control of three distinct loci, A, B, and C.

Animals↗

PubMed2006

Insufficient filling of vacuum tubes as a cause of microhemolysis and elevated serum lactate dehydrogenase levels. Use of a data-mining technique in evaluation of questionable laboratory test results.

Experienced physicians noted unexpectedly elevated concentrations of lactate dehydrogenase in some patient samples, but quality control specimens showed no bias. To evaluate this problem, we used a "latent reference individual extraction method", designed to obtain reference intervals from a laboratory database by excluding individuals who have abnormal results for basic analytes other than the analyte in question, in this case lactate dehydrogenase. The reference interval derived for the suspected year was 264-530 U/L, while that of the previous year was 248-495 U/L. The only change we found was the introduction of an order entry system, which requests precise sampling volumes rather than complete filling of vacuum tubes. The effect of vacuum persistence was tested using ten freshly drawn blood samples. Compared with complete filling, 1/5 filling resulted in average elevations of lactate dehydrogenase, aspartic aminotransferase, and potassium levels of 8.0%, 3.8%, and 3.4%, respectively (all p<0.01). Microhemolysis was confirmed using a urine stick method. The length of time before centrifugation determined the degree of hemolysis, while vacuum during centrifugation did not affect it. Microhemolysis is the probable cause of the suspected pseudo-elevation noted by the physicians. Data-mining methodology represents a valuable tool for monitoring long-term bias in laboratory results.

Adult↗

PubMed2001

Glucose metabolism and regulation of glycolysis in Lactococcus lactis strains with decreased lactate dehydrogenase activity.

The distribution of carbon flux at the pyruvate node was investigated in Lactococcus lactis under anaerobic conditions with mutant strains having decreased lactate dehydrogenase activity. Strains previously selected by random mutagenesis by H. Boumerdassi, C. Monnet, M. Desmazeaud, and G. Corrieu (Appl. Environ. Microbiol. 63, 2293-2299, 1997) were found to have single punctual mutations in the ldh gene and presented a high degree of instability. The strain L. lactis JIM 5711 in which lactate dehydrogenase activity was diminished to less than 30% of the wild type maintained homolactic metabolism. This was due to an increase in the intracellular pyruvate concentration, which ensures the maintained flux through the lactate dehydrogenase. Pyruvate metabolism was linked to the flux limitation at the level of glyceraldehyde-3-phosphate dehydrogenase, as previously postulated for the parent strain (C. Garrigues, P. Loubière, N. D. Lindley, and M. Cocaign-Bousquet (1997) J. Bacteriol. 179, 5282-5287, 1997). However, a strain (L. lactis JIM 5954) in which the ldh gene was interrupted reoriented pyruvate metabolism toward mixed metabolism (production of formate, acetate, and ethanol), though the glycolytic flux was not strongly diminished. Only limited production of acetoin occurred despite significant overflow of pyruvate. Intracellular metabolite profiles indicated that the in vivo glyceraldehyde-3-phosphate dehydrogenase activity was no longer flux limiting in the Deltaldh strain. The shift toward mixed acid fermentation was correlated with the lower intracellular trioses phosphate concentration and diminished allosteric inhibition of pyruvate formate lyase.

Base Sequence↗

PubMed1977

Lactate dehydrogenase isoenzymes in the human hypertrophic heart.

Lactate dehydrogenase isoenzymes have been measured in human hearts at autopsy. As compared with normal hearts, hypertrophic hearts and ischaemic hypertrophic hearts showed a shift in the isoenzyme distribution. This shift appeared to be more closely associated with an increase in the relative proportion of fibrous tissue than with changes in the myocardial cells.

Cardiomegaly↗

PubMed1983

One and two dimensional isoelectric focusing of lactate dehydrogenase from the tissues of ovis aries.

Lactate dehydrogenase in ovine tissues was separated by electrophoresis, one dimensional isoelectric focusing (IEF) and a two dimensional technique. Tissues showed five zones of enzyme activity consisting of multiple bands after IEF. The IEF zymograms were unique for each tissue and differed from those of other species. Two dimensional separation revealed that the five zones of activity observed on IEF corresponded to the five isoenzymes separable by conventional electrophoresis.

Animals↗

PubMed1983

Lactate dehydrogenase activity in ocular tumors.

Estimates of lactate dehydrogenase (LDH) activity in aqueous and serum was carried out on 15 cases of benign ocular tumor, 15 cases of malignant tumor, and 15 normal cases. LDH levels were high in serum and aqueous of cases with malignant tumor as compared to benign tumor and control cases. Total LDH activity in serum and aqueous was grossly elevated in malignant tumor cases (specially retinoblastoma).

Adolescent↗

PubMed1978

Metabolic and cellular profile testing in calves under feedlot conditions: protein fractions and lactate dehydrogenase isoenzymes--reference values.

Serum protein and lactate dehydrogenase (LDH) isoenzyme values were determined for frozen serum samples from crossbred yearling feedlot cattle on feed for 56 days. The mean percentage values for serum protein components from 114 samples were: albumin, 46.5; alpha-globulin, 10.4; beta-globulin, 18.7; gamma-globulin, 23.8. For LDH isoenzymes, they were: LDH1, 36.5; LDH2, 24.7; LDH3, 16.9; LDH4, 12.0; LDH5, 9.1. These values are compared with values from dairy cattle.

Animal Feed↗