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The resolution of some steps of the reactions of lactate dehydrogenase with its substrates.

1. The reaction of pig heart lactate dehydrogenase (EC 1.1.1.27) with NAD(+) and lactate to form pyruvate and NADH was followed by rapid spectrophotometric methods. The distinct spectrum of enzyme-bound NADH permits the measurement of the rate of dissociation of this compound. 2. The reduction of the first mole equivalent of NAD(+) per mole of enzyme sites can also be observed, and is much more rapid than the steady-state rate of NADH production. 3. At pH8 the dissociation of the enzyme-NADH complex is rate-determining for the steady-state oxidation of lactate. At lower pH some other step after the interconversion of the ternary complex and before the dissociation of NADH is rate-determining. Other evidence for a compulsory-order mechanism is provided.

Animals↗

Cloning of the gene for the respiratory D-lactate dehydrogenase of Escherichia coli.

During attempts to clone the gene coding for the respiratory NADH dehydrogenase of Escherichia coli, two hybrid plasmids were constructed from E. coli chromosomal DNA [Young, I. G., Jaworowski, A., & Poulis, M. I. (1978) Gene 4, 25-36]. One of these plasmids, pIY1, derived from EcoRI-digested chromosomal DNA, was studied in detail and shown to possess the gene coding for the NADH dehydrogenase of the aerobic respiratory chain of E. coli. We now report the characterization of the other hybrid plasmid, pIY2, derived from HindIII-digested chromosomal DNA, and shown that it complements ndh mutants not by virtue of carrying the ndh gene but because it carries the gene coding for the respiratory D-lactate dehydrogenase. Cells carrying this hybrid plasmid overproduce the respiratory D-lactate dehydrogenase in their cell membranes by 15-20-fold with negligible activity appearing in the cytoplasm. This results in an amplification of the levels of the D-lactate oxidase. The amplified D-lactate oxidase activity, coupled with the pyridine nucleotide linked D-lactate dehydrogenase, apparently provides a new pathway for the oxidation of reduced nicotinamide adenine dinucleotide (NADH) in the cell, independent of the respiratory NADH oxidase.

Cloning, Molecular↗

Cloning, nucleotide sequence, expression, and chromosomal location of ldh, the gene encoding L-(+)-lactate dehydrogenase, from Lactococcus lactis.

A gene (designated ldh) that encodes fructose-1,6-bisphosphate-activated L-(+)-lactate dehydrogenase was cloned from Lactococcus lactis subsp. lactis. Plasmids containing ldh conferred fructose-1,6-bisphosphate-activated L-(+)-lactate dehydrogenase activity on Escherichia coli cells. This activity was conferred only when a promoter had been introduced into the plasmid to express the cloned ldh. The nucleotide sequence of ldh predicted a chain length of 324 amino acids and a subunit molecular weight of 34,910 for the enzyme, after removal of the N-terminal methionine residue. Northern analyses of L. lactis subsp. lactis RNA showed that a 4.1-kb transcript hybridized strongly with ldh and that 1.2- and 1.1-kb transcripts hybridized to much lesser extents. Promoter- and terminator-cloning studies in which we used the vectors pGKV210 and pGKV259 in L. lactis subsp. lactis revealed that the 5' flanking DNA of ldh is devoid of transcription initiation signals and that transcription entering the 3' flanking DNA from either direction is efficiently terminated. These data and the data from Northern analyses led to the conclusion that ldh is expressed as the 3' gene of the 4.1-kb transcript and suggested that posttranscriptional processing yielded the shorter transcripts. We determined that ldh is located on the L. lactis subsp. lactis chromosome between coordinates 1.619 and 1.669 of the previously reported physical map (D. L. Tulloch, L. R. Finch, A. J. Hillier, and B. E. Davidson, J. Bacteriol. 173:2768-2775, 1991).

Amino Acid Sequence↗

[Adenosine triphosphatase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity of pancreas of thyroidectomized rats].

Activity of enzymes catalizing bioenergetic processes of substance transport through cell membranes, adenosine triphosphatase and para-nitrophenyl phosphates, activity of certain enzymes of carbohydrate metabolism, lactate dehydrogenase and glucose-6-phosphate dehydrogenase, as well as to 5'-nucleotidase taking part in nucleic metabolism were determined in the pancreas of thyreoidectomized rats. Simultaneously the content of lactic acid, phosphorus, potassium and sodium, which immediately related to activation of the mentioned enzymes, was determined in the pancreas. In thyroidectomized rats the activity of Mg2+, Na+, K+-ATPase, Na+, K+-ATPase and lactate dehydrogenase in the pancreas increases, that of glucose-6-phosphate dehydrogenase, para-nitrophenylphosphatase and 5-nucleotidase decreases, the content of lactic acid, potassium, sodium and phosphorus increases.

4-Nitrophenylphosphatase↗

The relationship between fibrosis and lactate dehydrogenase isoenzymes in the experimental hypertrophic heart of rabbits.

Cardiac hypertrophy was induced in rabbits by injecting either thyroxine or isoprenaline or by surgically constricting the abdominal aorta. An increase in heart weight was associated with a change in the lactate dehydrogenase isoenzyme pattern and an increase in fibrosis (as measured by hydroxyproline concentrations). Isoprenaline treatment led to a moderate increase in heart weight, a marked decrease in the heart/skeletal muscle subunit ratio of lactate dehydrogenase, and a marked increase in hydroxyproline. Thyroxine treatment led to a small increase in both heart weight and hydroxyproline and a small decrease in the heart/skeletal muscle subunit ration. Coarctation of the aorta, in contrast, caused a marked increase in heart weight, a moderate decrease in heart/skeletal muscle subunit ratio, and a moderate increase in hydroxyproline. These results suggest that the decrease in the heart/skeletal muscle subunit ratio of lactate dehydrogenase in the experimental hypertrophic heart reflects the extent of myocardial fibrosis, rather than changes within the hypertrophied myocardial cells.

Animals↗

Exploitation of the broad specificity of the membrane-bound isoenzyme of lactate dehydrogenase for direct selection of null mutants in Neisseria gonorrhoeae.

Lactic acid is readily utilized as a carbon and energy source by Neisseria gonorrhoeae. The oxidation of lactate is coupled to electron transport via a membrane-bound lactate dehydrogenase (iLDH) which is independent of pyridine nucleotide. The broad substrate specificity of iLDH endows N. gonorrhoeae with the novel ability to convert phenyllactate to L-phenylalanine via phenylpyruvate. N. gonorrhoeae ATCC 27628 typifies a class of clinical isolate whose growth is inhibited by phenylpyruvate (or L-phenylalanine). Exploiting resistance to growth inhibition by phenyllactate as a strategy of positive selection, mutant derivatives of strain ATCC 27628 lacking iLDH activity were readily obtained. These mutants are incapable of oxidizing phenyllactate, and lack the parent-strain ability to reduce c-type cytochromes in the presence of lactate, phenyllactate or 4-hydroxyphenyllactate. They retain, however, a cytoplasmic NAD(+)-linked lactate dehydrogenase (nLDH). Since the mutants retained the ability to grow on lactate as a sole source of carbon, nLDH presumably can function in an opposite-to-normal physiological direction in the absence of iLDH. This would explain the failure to isolate iLDH-deficient mutants by selection for inability to grow on lactate.

Drug Resistance, Microbial↗

POLYMORPHISM OF HUMAN LACTATE DEHYDROGENASE ISOZYMES.

Of 1200 individuals screened, four had variant erythrocyte lactate dehydrogenases. Three of these, identical electrophoretically to the Mem-1 described by Kraus and Neely, were heterozygous variants involving the a-locus. The fourth, involving the b-locus, appears to be the first example in man of a homozygous variant.

Black People↗

LACTATE DEHYDROGENASE ISOZYMES: LABILITY AT LOW TEMPERATURE.

A change in the lactate dehydrogenase isozyme pattern can arise when human tissue homogenates are kept at -20 degrees C. This change is most pronounced in a homogenate with a pH of about 7.9 in barbital buffer and is not seen when nicotinamide adeninedinucleotide is added to the homogenates before freezing, nor when the homogenates are kept at room temperature, nor when the tissue alone is kept at -20 degrees C.

Chemical Phenomena↗

Method variation in lactate dehydrogenase isoenzyme determination.

Differences between methods for determining lactate dehydrogenase isoenzymes are illustrated, which can account for discrepant results. They should be taken into consideration in the interpretation of test results for the diagnosis of myocardial infarction.

Colorimetry↗

Expression of lactate dehydrogenase A and B genes in different tissues of rats adapted to chronic hypobaric hypoxia.

Lactate dehydrogenase (LDH) is a tetramer made up of two different subunits A and B. In cellular models, severe hypoxia increases LDH A gene expression whereas LDH B gene does not exhibit any regulation. The aim of our work was to characterise LDH expression in different tissues of rats bred at high altitude. For this purpose, we chose a Sprague-Dawley rat strain adapted to chronic hypoxia in La Paz (3700 m), Bolivia. Two normoxic control groups were bred at low altitude in Clermont-Ferrand (350 m), France, one group was ad libitum with free access to food and water as was the hypoxic one, and the second normoxic group was nourished with the food intakes measured for the animals from La Paz. We measured total LDH specific activity, isoform distribution and LDH A and B mRNA amounts in three skeletal muscles (soleus, extensor digitorum longus (EDL), plantaris), heart and brain. Our study demonstrates that, unlike what has been shown in cellular models under severe hypoxia, LDH A gene is not systematically up-regulated in tissues of rats living at high altitude. Furthermore, chronic hypoxia limits LDH B gene transcription or its mRNA stability in both soleus and EDL. These regulations occur at various molecular levels like gene transcription, mRNA stabilisation or translation and protein stability, depending on the tissue studied, and are partly attributed to caloric restriction provoked by high altitude. These data provide insight into LDH gene expression underlying the diverse and complex tissue-specific response to chronic hypoxia.

Adaptation, Physiological↗

A simple and economical procedure for purification of muscle lactate dehydrogenase by batch dye-ligand adsorption.

A simple, economical and rapid purification procedure for muscle lactate dehydrogenase is described. It makes use of batch adsorption on Procion Red H-3B coupled to agarose through an amine linkage. The enzyme is eluted with NAD+ and sulphite, and for many purposes no more processing is necessary. Only 70 ml settled volume of adsorbent is required to process extract containing 1 g of lactate dehydrogenase, which is recovered with up to 90% yield, at over 98% purity. The method is readily scalable up or down, and makes an excellent class demonstration of affinity techniques.

Adsorption↗

Properties of lactate dehydrogenase from the isopod, Saduria entomon.

Saduria entomon lactate dehydrogenase (LDH-A4*) from thorax muscle was purified about 89 fold to specific activity 510 micromol NADH/min/mg using Cibacron Blue 3GA Agarose and Oxamate-Agarose chromatographies. The enzyme is a tetramer, with molecular weight of 140 kDa for the native enzyme and 36 kDa for the subunit. The isoelectric point was at pH 5.7. The enzyme possesses high heat stability (T50 = 71.5 degrees C). The optimum pH for pyruvate reduction reaction was 6.5, while for lactate oxidation one, the maximum activity was at pH 9.1. The Km for pyruvate was minimal at 5 degrees C, the average environmental temperature of the isopod. The Km values determined at 30 degrees C and optimal pH for pyruvate reduction and lactate oxidation were 0.18 and 90.04 mM, respectively. Amino acid compositional analyses showed the strongest resemblance of the isopod isoenzyme to cod (Gadus morhua) LDH-C4.

Animals↗

Molecular genetic studies of muscle lactate dehydrogenase deficiency in white patients.

We identified two new mutations in 2 white patients with muscle lactate dehydrogenase deficiency. Both patients had exercise intolerance, cramps, and recurrent myoglobinuria. One patient was homozygous for a 2-bp deletion in exon 5, resulting in a frameshift with premature termination of translation. The second patient was homozygous for a G-->A substitution at the 3' end of exon 2, leading to exon skipping and splicing of exon 1 to exon 3; the aberrantly spliced messenger RNA contains a frameshift, resulting in premature termination of translation. The present report provides evidence of molecular genetic heterogeneity in white patients with muscle lactate dehydrogenase deficiency.

Adult↗

Regional distribution of lactate dehydrogenase isoenzymes in adult rat brain.

The highest lactate dehydrogenase (LDH) activity was found in thalamus, statistically significantly less in cerebral and cerebellar cortex and the lowest in pons. LDH1 and LDH4+5 represented 58% and 23% of the total activity in cerebral cortex, 54% and 20% in thalamus, 42% and 4% in cerebellar cortex and 55% and 7% in pons, respectively.

Animals↗

[The mechanism of action of chorionic gonadotropin on lactate dehydrogenase activity].

The purpose of this report is to demonstrate that chorionic gonadotropin (CG) interacts nonspecifically with lactate dehydrogenase changing its catalytic activity. The binding in vitro of CG (5 mg/ml) to the enzyme is accompanied by conformational changes of its protein and kinetic characteristics. It may be possible that chorionic gonadotropin exercises a controlling influence on lactate dehydrogenase activity in the cell.

Animals↗

The putative L-lactate dehydrogenase from Methanococcus jannaschii is an NADPH-dependent L-malate dehydrogenase.

The enzyme encoded by Methanococcus jannaschii open reading frame (ORF) 0490 was purified and characterized. It was shown to be an NADPH-dependent [lactate dehydrogenase (LDH)-like] L-malate dehydrogenase (MalDH) and not an L-lactate dehydrogenase, as had been suggested previously on the basis of amino acid sequence similarity. The results show the importance of biochemical data in the assignment of ORF function in genomic sequences and have implications for the phylogenetic distribution of members of the MalDH/LDH enzyme superfamilies within the prokaryotic kingdom.

Circular Dichroism↗

Vesicles with lactate dehydrogenase and without alkaline phosphatase present in the resting zone of epiphyseal cartilage.

Matrix vesicles are membrane-invested vesicles that initiate mineralization in the extracellular matrix of calcifying tissues. The epiphyseal cartilages of young-rat rib bones were divided into the growth zone and the resting zone, followed by the isolation of matrix vesicles after collagenase treatment. Matrix vesicles with both alkaline phosphatase and lactate dehydrogenase were detected in the growth cartilage found in the epiphyseal growth plates of young rabbits [Hosokawa, Uchida, Fujiwara & Noguchi (1988) J. Biol. Chem. 263, 10045-10047], but were not detected in the resting zone. By contrast, and surprisingly, lactate dehydrogenase-containing vesicles without alkaline phosphatase were found in the resting zone, but not in the growth zone. In both the growth and resting zones, isoenzyme patterns of lactate dehydrogenase in the two different vesicles were identical with those of cytosolic lactate dehydrogenase of chondrocytes, suggesting the presence of a mechanism for specific uptake of cytosolic lactate dehydrogenase. The same results as for young-rat rib bones were obtained with the resting and growth cartilages of young-dog and monkey rib bones.

Alkaline Phosphatase↗

Identification of putative mammalian D-lactate dehydrogenase enzymes.

Mammalian L-isomer dehydrogenases represent an expansive and well characterized class of metabolic enzymes. Surprisingly, little is known regarding their evolutionarily distinct counterparts, D-isomer dehydrogenases, since few mammalian D-isomer 2-hydroxy acid enzymes have been isolated. Here we present the identification and initial characterization of putative human and murine D-lactate dehydrogenases (DLD) that can interact with the muscle-specific cysteine-rich protein CRP3/MLP. Sequence analysis reveals that the human and mouse transcripts encode novel proteins that display strong similarities to the yeast D-lactate dehydrogenase proteins DLD1, AIP2, and YEL071W. Expression analysis of the mammalian proteins indicates widespread distribution with transcripts present in striated muscle tissues and a variety of other tissue types. Immunofluorescence subcellular localization of the mouse DLD protein indicates that it resides within mitochondria, a feature shared by many dehydrogenases. The identification of the human and mouse DLD clones provides new insight regarding the activity of D-isomer-specific enzymes in mammalian cells.

Amino Acid Motifs↗