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[An optimum regimen for the use of malate dehydrogenase and lactate dehydrogenase during chemical regeneration of the cofactor].

The steady-state kinetics of malate oxidation by malate dehydrogenase was being studied without coupling reagents under the conditions of chemical regeneration of the cofactor by the following pairs: phenazine methosulphate (PMS)--dichlorphenolindophenol (DCPIP) and PMS--tetranitrotetrazolium blue (TNTB). The comparative kinetic study was carried out of the steady-state oxidation of lactate and the reduction of pyruvate by lactate rehydrogenase, as well as of the dehydrogenation of lactate, coupled with the cofactor regeneration by the pair PMS-DCPIP. Optimum reagent concentrations, optimum pH and activation energies were determined for six systems. Malate dehydrogenation coupled with regeneration of the cofactor by the pair PMS-TNTB is the most promising reaction for enzyme immunoassay.

Animals↗
PubMed1987

[Effect of short-term exposure to ash from electric power plants on histochemical reactions of succinate dehydrogenase and lactate dehydrogenase in the lungs of experimental animals].

Histochemical studies of the activity of succinic dehydrogenase (SDH) and lactic dehydrogenase (LDH) in the pulmonary tissue of experimental animals which were given four coal ashes issued from different thermal-electric power stations: group VII--from the thermal-electric power station Siekierki (Warsaw), group VIII--from Wrocław, group IX--from Leg (Cracow) and group XI--from Lódź, were carried out. In particular ash samples the content of trace elements and free silica was determined. The studies yield the following conclusions: 1. The activity of succinic dehydrogenase (SDH) and lactic dehydrogenase (LDH) was changed in the respiratory tract and pulmonary alveoli as a result of the electroenergetic ashes applied. 2. Changes in cytoenzymatic reactions of SDH and LDH vary with the type of ash applied. The greatest changes were found in group XI where the ashes contained almost doubled amount of such elements as Mn, Zn, Pb, Cu. 3. SDH exhibited a greater sensitivity to the effects of electroenergetic ashes, as compared to LDH. 4. Changes in the activity of the test SDH and LDH enzymes indicate disorders in oxydoreductory processes of cells.

Aerosols↗
PubMed2003

Functional replacement of the Escherichia coli D-(-)-lactate dehydrogenase gene (ldhA) with the L-(+)-lactate dehydrogenase gene (ldhL) from Pediococcus acidilactici.

The microbial production of L-(+)-lactic acid is rapidly expanding to allow increased production of polylactic acid (PLA), a renewable, biodegradable plastic. The physical properties of PLA can be tailored for specific applications by controlling the ratio of L-(+) and D-(-) isomers. For most uses of PLA, the L-(+) isomer is more abundant. As an approach to reduce costs associated with biocatalysis (complex nutrients, antibiotics, aeration, product purification, and waste disposal), a recombinant derivative of Escherichia coli W3110 was developed that contains five chromosomal deletions (focA-pflB frdBC adhE ackA ldhA). This strain was constructed from a D-(-)-lactic acid-producing strain, SZ63 (focA-pflB frdBC adhE ackA), by replacing part of the chromosomal ldhA coding region with Pediococcus acidilactici ldhL encoding an L-lactate dehydrogenase. Although the initial strain (SZ79) grew and fermented poorly, a mutant (SZ85) was readily isolated by selecting for improved growth. SZ85 exhibited a 30-fold increase in L-lactate dehydrogenase activity in comparison to SZ79, functionally replacing the native D-lactate dehydrogenase activity. Sequencing revealed mutations in the upstream, coding, and terminator regions of ldhL in SZ85, which are presumed to be responsible for increased L-lactate dehydrogenase activity. SZ85 produced L-lactic acid in M9 mineral salts medium containing glucose or xylose with a yield of 93 to 95%, a purity of 98% (based on total fermentation products), and an optical purity greater than 99%. Unlike other recombinant biocatalysts for L-lactic acid, SZ85 remained prototrophic and is devoid of plasmids and antibiotic resistance genes.

Culture Media↗
PubMed2004

Major role of NAD-dependent lactate dehydrogenases in aerobic lactate utilization in Lactobacillus plantarum during early stationary phase.

NAD-independent lactate dehydrogenases are commonly thought to be responsible for lactate utilization during the stationary phase of aerobic growth in Lactobacillus plantarum. To substantiate this view, we constructed single and double knockout mutants for the corresponding genes, loxD and loxL. Lactate-to-acetate conversion was not impaired in these strains, while it was completely blocked in mutants deficient in NAD-dependent lactate dehydrogenase activities, encoded by the ldhD and ldhL genes. We conclude that NAD-dependent but not NAD-independent lactate dehydrogenases are involved in this process.

Acetates↗
PubMed1990

The cDNA and protein sequences of mouse lactate dehydrogenase B. Molecular evolution of vertebrate lactate dehydrogenase genes A (muscle), B (heart) and C (testis).

Mouse lactate dehydrogenase-B cDNAs were isolated from cDNA libraries of macrophage (ICR strain) and thymus (F1 hybrid of C57BL/6 and CBA strains), and their nucleotide sequences determined. The lactate dehydrogenase-B cDNA insert of thymus clone mB188 consists of the protein-coding sequence (1002 nucleotides), the 5' (46 nucleotides) and 3' (190 nucleotides) non-coding regions, and poly(A) tail (19 nucleotides), while macrophage clone mB168 contains a partial lactate dehydrogenase cDNA insert from codon no. 55 to the poly(A) tail. Seven silent nucleotide substitutions at codon no. 142, 143, 186, 187, 241, 285 and 292, as well as a single nucleotide change in the 3' non-coding region, were found between these different strains of mice. The predicted sequence of 333 amino acids, excluding initiation methionine, was confirmed by sequencing and/or compositional analyses of a total of 103 (31%) amino acids from tryptic peptides of mouse lactate dehydrogenase-B protein. The nucleotide sequence of the mouse coding region for lactate dehydrogenase B shows 86% identity with that of the human isoenzyme, and only eight of the 139 nucleotide differences resulted in amino acid substitutions at residues 10, 13, 14, 17, 52, 132, 236 and 317. The rates of nucleotide substitutions at synonymous and nonsynonymous sites in the mammalian lactate dehydrogenase genes are calculated. The rates of synonymous substitutions for lactate dehydrogenase genes A (muscle) and B (heart) are considerably higher than the average rate computed from human and rodent genes. The rates of nonsynonymous substitutions for lactate dehydrogenase genes A (muscle) and B (heart), particularly the latter, are highly conservative. The rates of synonymous and nonsynonymous substitutions for the lactate dehydrogenase-C gene are about the same as the average rates for mammalian genes. A phylogenetic tree of vertebrate lactate dehydrogenase protein sequences is constructed. In agreement with the previous results, this analysis further indicates that lactate dehydrogenase-C gene branched off earlier than did lactate dehydrogenase-A and lactate dehydrogenase-B genes.

Amino Acid Sequence↗
PubMed1983

Mitochondrial NAD, L-lactate dehydrogenase and NAD, D-lactate dehydrogenase in the yeast Saccharomyces cerevisiae.

Mitochondrial NAD-linked L- and D-lactate dehydrogenase activities have been found in the yeast Saccharomyces cerevisiae grown at high (3%) but were absent at low (0.6%) glucose concentrations. The inhibition of mitochondrial protein synthesis by chloramphenicol and of primary respiration by antimycin A determines the appearance of the two activities even at low (0.6%) glucose concentration. Two respiratory deficient strains belonging respectively to the mit- class (which maintains mitochondrial protein synthesis) and to the rho- class (which loses mitochondrial protein synthesis) display the activities even at low (0.6%) glucose concentration. L- and D-lactate have been detected in the growth medium when the cultures had been undertaken at high glucose concentrations, but were absent at low glucose concentrations.

Anaerobiosis↗
PubMed1982

H-2-controlled suppression of T cell response to lactate dehydrogenase B. Characterization of the lactate dehydrogenase B suppressor pathway.

We characterized the cell types involved in the H-2-controlled suppression of T cell response to lactate dehydrogenase B (LDHB). The suppressor effector (Tse) was found to be an Lyt-1+2+, J+ cell that recognizes antigen together with Ek molecules of antigen-presenting cells (APC). To become functional, the Tse cell requires a second signal from a nonspecific, Lyt-1+2-, J+ suppressor-inducer (Tsi) cell. The Tsi-Tse interaction is not subject to any genetic restriction. The target cell of suppression is an Lyt-1+2-, J- (most likely T helper [Th]) cell that recognizes LDHB in the context of A molecules on APC. The suppression is manifested in inhibition of the antigen-specific, A-restricted proliferation of Th cells. The interaction between Tse and Th is restricted by the A region of the H-2 complex. Because this restriction is determined by the receptor of Th cells, the mechanism of Th-Tse interaction most likely involves a concomitant recognition of LDHB and A region-controlled molecules by Th cells on the surface of Tse cells.

Animals↗
PubMed1995

Rapid and easy procedure for the determination of immunoglobulin class and light chain type of anti-lactate dehydrogenase antibodies in macro-lactate dehydrogenase.

We developed an easy to perform and rapid method for determination of the immunoglobulin class and light chain type of anti-enzyme antibodies present in macro-enzymes. The procedure is a combination of two routinely used laboratory kits, and it allows identification of the antibody involved within 1.5 hour. The applicability of the method was demonstrated for macro-lactate dehydrogenase.

Anemia, Hemolytic↗
PubMed1987

Structure and function of L-lactate dehydrogenases from thermophilic and mesophilic bacteria. VII. Nucleotide sequence of the lactate dehydrogenase gene from the mesophilic bacterium Bacillus megaterium. Preparation and properties of a hybrid lactate dehydrogenase comprising moieties of the B. megaterium and B. stearothermophilus enzymes.

The lactate dehydrogenase (LDH) gene of a mesophilic bacterium, Bacillus megaterium (DSM 090), was cloned in E. coli HB 101 using a pEMBL vector and synthetic oligonucleotide probes. The gene was strongly expressed in the vector used if the orientation of the insert allowed the LDH promoter and the vector's lac promoter to direct transcription in the same direction. The gene and its 5' and 3' flanking regions have been sequenced. Codon usage patterns of LDH genes from mesophilic and thermophilic bacilli were compared and found to be characteristically different. A hybrid gene was constructed from fragments of the LDH genes from B. stearothermophilus (coding for aa 15-100) and B. megaterium (coding for aa 101-331). The hybrid LDH, named S100M, was more thermostable than B. megaterium LDH, less thermostabile than B. stearothermophilus LDH and unlike the two wildtype enzymes, it could not be activated by Fru-P2.

Bacillus megaterium↗
PubMed1969

Immunochemical homologies among subunits of trout lactate dehydrogenase isozymes.

Lactate dehydrogenase is a tetrameric enzyme, generally composed of one or two kinds of subunits each encoded in a separate gene. Most vertebrates synthesize five major isozymic forms of lactate dehydrogenase, but the salmonid fish, particularly trout, synthesize many more. The numerous lactate dehydrogenase isozymes of trout can be selectively removed from tissue homogenates by suitably prepared antisera to specific lactate dehydrogenase subunits of fish. Electrophoretic resolution of such antisera-treated homogenates then permits an identification of each isozyme and a determination of its subunit composition and probable genetic basis. Such data indicate that trout are tetraploid organisms and have duplicate and slightly different loci for two and perhaps three of the lactate dehydrogenase loci found in other fish. The evolutionary relationships among the lactate dehydrogenase loci can also be assessed by these immunochemical data.

Animals↗