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PubMed1995

Isoenzyme patterns of glucose-6-phosphate dehydrogenase, malate dehydrogenase and lactate dehydrogenase in Babesia rodhaini and Babesia microti.

Glucose-6-phosphate dehydrogenase (G6PD), malate dehydrogenase (MDH), and lactate dehydrogenase (LDH) activities and their isoenzyme patterns in B. rodhaini (BR) and B. microti (BM), the two major causative species of murine babesiosis, were examined. G6PD and LDH activities were higher in BR than those in BM, whereas MDH activity was lower in BR than that in BM. No differences were observed between BR and BM in the mobility of isoenzyme bands of G6PD and MDH. On LDH isoenzyme pattern, at least 5 bands were detected in BR, while only one band in BM. Since each subunit of LDH is known to be coded by different gene, these results suggests that BR and BM are able to be differentiated genetically.

Animals↗
PubMed1989

Examination of HeLa cell contamination of human cell lines derived from primary hepatomas using glucose-6-phosphate dehydrogenase and lactate dehydrogenase isozymes.

Isozyme patterns of glucose-6-phosphate dehydrogenase (G6PD) and lactate dehydrogenase (LDH) in human cell lines derived from primary hepatomas were compared with those in HeLa cells. Some cell lines derived from primary hepatomas having type B G6PD showed one or two isozymes of LDH. On the other hand, HeLa cells having type A G6PD showed four LDH isozymes. These findings suggest that not only G6PD, but also LDH may be useful for the detection of HeLa cell contamination of a culture in some cases.

Carcinoma, Hepatocellular↗
PubMed1994

Molecular weight of cytoplasmic malate dehydrogenase, mitochondrial malate dehydrogenase and lactate dehydrogenase of a freshwater catfish.

The multiple molecular forms of cytoplasmic malate dehydrogenase (cMDH), mitochondrial malate dehydrogenase (mMDH) and lactate dehydrogenase (LDH) were studied in the liver and skeletal muscle of the freshwater catfish, Clarias batrachus. There were two electrophoretically distinguishable bands (AA and BB) of cMDH and mMDH which suggests that they are apparently encoded at two gene loci (A and B) in both the tissues. However, the presence of a single band (LDH-1) of LDH in liver and double bands (LDH-1 and LDH-2) in skeletal muscle in which LDH-2 was predominant reflects the differential expression of LDH genes in different metabolic tissues to meet the requirement of energy production. The AA isoform (74 kd) of liver cMDH was smaller than those of the AA form (110 kd) of skeletal muscle. In contrast, the BB isoform of liver (42 kd) and skeletal muscle (54 kd) were more or less similar in size. Unlike the case of cMDH, the molecular weight of AA isoform (115 kd) of liver mMDH was higher than those of the AA form (87 kd) of skeletal muscle. Whereas the molecular weight of BB isoform (58 kd) of liver was in proximity to the weight of BB form (44 kd) of skeletal muscle mMDH. The size of AA isoform (74 kd) of liver cMDH was smaller, while the AA isoform (110 kd) of skeletal muscle was larger as compared to AA form of mMDH in the liver (115 kd) and skeletal muscle (87 kd). But the size of BB isoform of both the isozymes was almost equal in these metabolic tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Presence of lactate dehydrogenase and lactate racemase in Megasphaera elsdenii grown on glucose or lactate.

Activity of D-lactate dehydrogenase (D-LDH) was shown not only in cell extracts from Megasphaera elsdenii grown on DL-lactate, but also in cell extracts from glucose-grown cells, although glucose-grown cells contained approximately half as much D-LDH as DL-lactate-grown cells. This indicates that the D-LDH of M. elsdenii is a constitutive enzyme. However, lactate racemase (LR) activity was present in DL-lactate-grown cells, but was not detected in glucose-grown cells, suggesting that LR is induced by lactate. Acetate, propionate, and butyrate were produced similarly from both D- and L-lactate, indicating that LR can be induced by both D- and L-lactate. These results suggest that the primary reason for the inability of M. elsdenii to produce propionate from glucose is that cells fermenting glucose do not synthesize LR, which is induced by lactate.

Acetates↗
PubMedDate not supplied

False-positive postmortem EMIT drugs-of-abuse assay due to lactate dehydrogenase and lactate in urine.

Three cases of multiple false-positive drug tests are described. Postmortem urine specimens were screened using the enzyme-multiplied immunoassay technique. All patients had proteinuria and lactic aciduria. These false-positive reactions were due to the presence of lactate dehydrogenase (LDH), lactic acid, and protein. This finding was confirmed by creating a multiple false-positive sample with a solution of LDH and lactate in 5% bovine serum albumin at pH 6.

Adult↗
PubMed1988

Antibodies against alcohol dehydrogenase and lactate dehydrogenase inhibit the activities of other unrelated NADH-requiring dehydrogenases.

Polyclonal rabbit antibodies to NADH-requiring enzymes such as yeast alcohol-dehydrogenase (ADH) and lactate-dehydrogenase (LDH) immunoinhibit the activities of other unrelated dehydrogenases. The immunoinhibition of malate-dehydrogenase (MDH) activity by anti-yeast ADH IgG and anti-hog LDH IgG was dependent on the concentration of antibodies and time. This demonstration of cross-reactivity with unrelated enzyme proteins reveals the existence of an antigenic site around the NADH binding region in each of these enzymes. Pre-treatment of the enzyme with NADH resulted in complete protection against immuno-inactivation. The competitive binding of NADH and the ineffectiveness of ATP establish the difference in the antigenic site around the NADH- and ATP-binding region.

Alcohol Dehydrogenase↗
PubMed1994

Expression cloning of the nox, mdh and ldh genes from Thermus species encoding NADH oxidase, malate dehydrogenase and lactate dehydrogenase.

The Thermus thermophilus HB8 mdh and ldh genes and the T. aquaticus EP00276 nox and mdh genes encoding the biotechnologically important enzymes NADH oxidase (EC 1.6.99.3), malate dehydrogenase (EC 1.1.1.37) and lactate dehydrogenase (EC 1.1.1.27) were cloned on the basis of known sequences from related species using the polymerase chain reaction. The nox and mdh genes were directly placed under the control of regulatory expression elements from Escherichia coli. When the 5'-portions of the re-cloned nox gene and the mdh gene of T. thermophilus HB8 were simultaneously altered, enzyme yields of 18-42% of the total soluble cellular protein were obtained as compared to 2-6% obtained from the unchanged genes. The high overproduction level upon the alterations can be explained by the occurrence of additional potential base pairs between nucleotides in the mRNA downstream of the start codon ('downstream box') and the 16S rRNA. An 'universal translation initiation sequence' providing such strong interactions may be of general use for high overproduction levels.

Base Sequence↗
PubMed1989

Direct transfer of NADH between alpha-glycerol phosphate dehydrogenase and lactate dehydrogenase: fact or misinterpretation?

Following the criticism by Chock and Gutfreund [Chock, P.B. & Gutfreund, H. (1988) Proc. Natl. Acad. Sci. USA 85, 8870-8874], that our proposal of direct transfer of NADH between glycerol-3-phosphate dehydrogenase (alpha-glycerol phosphate dehydrogenase, alpha-GDH; EC 1.1.1.8) and L-lactate dehydrogenase (LDH; EC 1.1.1.27) was based on a misinterpretation of the kinetic data, we have reinvestigated the transfer mechanism between this enzyme pair. By using the "enzyme buffering" steady-state kinetic technique [Srivastava, D.K. & Bernhard, S.A. (1984) Biochemistry 23, 4538-4545], we examined the mechanism (random diffusion vs. direct transfer) of transfer of NADH between rabbit muscle alpha-GDH and pig heart LDH. The steady-state data reveal that the LDH-NADH complex and the alpha-GDH-NADH complex can serve as substrate for the alpha-GDH-catalyzed reaction and the LDH-catalyzed reaction, respectively. This is consistent with the direct-transfer mechanism and inconsistent with a mechanism in which free NADH is the only competent substrate for either enzyme-catalyzed reaction. The discrepancy between this conclusion and that of Chock and Gutfreund comes from (i) their incorrect measurement of the Km for NADH in the alpha-GDH-catalyzed reaction, (ii) inadequate design and range of the steady-state kinetic experiments, and (iii) their qualitative assessment of the prediction of the direct-transfer mechanism. Our transient kinetic measurements for the transfer of NADH from alpha-GDH to LDH and from LDH to alpha-GDH show that both are slower than predicted on the basis of free equilibration of NADH through the aqueous environment. The decrease in the rate of equilibration of NADH between alpha-GDH and LDH provides no support for the random-diffusion mechanism; rather, it suggests a direct interaction between enzymes that modulates the transfer rate of NADH. Thus, contrary to Chock and Gutfreund's conclusion, all our experimental data compel us to propose, once again, that NADH is transferred directly between the sites of alpha-GDH and LDH.

Animals↗
PubMed1977

[Histochemistry of glucosephosphate dehydrogenase and lactate dehydrogenase of the neural cells of chick embryo].

A high intensity of the reactions to lactate dehydrogenase and glucous-6-phosphate dehydrogenase was demonstrated histochemically in the neural anlage of the chick embryos after 15, 20, 24, 30, 44, 48 and 72 hours of incubation. At early stages of the development cranio-caudal gradient of enzymatic reactions was distinctly traced. A high intensity of the reactions was observed in certain cells of the neural groove in 24-hours' embryos and in the neural tube of 48-hours' embryos. These cells are supposed to develop into neuroblasts.

Animals↗
PubMed1993

Metabolite-modulated complex formation between alpha-glycerophosphate dehydrogenase and lactate dehydrogenase.

A modified Hummel-Dreyer equilibrium chromatography technique was used to test the hypothesis that NADH induces the molecular association of lactate dehydrogenase (LDH) and alpha-glycerol-3-phosphate dehydrogenase (alpha-GDH). In the presence of a very limited NADH concentration, a unique elution profile with a new peak running immediately ahead of a trough at the free alpha-GDH elution position is obtained. The appearance of this peak-trough profile is physical evidence that reversible association between LDH and alpha-GDH occurs over a very limited range of free NADH concentrations. The association constant for this complex formation between LDH and alpha-GDH is estimated to be 2.0 microM-1. With the NADH concentration increased to saturation level, no evidence of binding is observed. Such concentration-dependent behavior suggests that the strong competition between LDH and alpha-GDH for the limited amount of NADH tends to promote the enzyme-enzyme contact in order to make the most efficient use of the shared metabolite. The experimental results described in this article make a convincing argument for a metabolite-modulated enzyme-enzyme interaction along this metabolic pathway.

Binding, Competitive↗
PubMed1989

Induction of alcohol dehydrogenase and lactate dehydrogenase in hypoxically induced barley.

In barley (Hordeum vulgare L.), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) are induced by anaerobiosis in both aleurone layers and roots. Under aerobic conditions, developing seeds of cv Himalaya accumulate ADH activity, which survives seed drying and rehydration. This activity consists almost entirely of the ADH1 homodimer. Activity of LDH also increases during seed development, but the level of activity in dry or rehydrated seeds is very low, indicating that this enzyme may not be involved in anaerobic glycolysis during the initial stages of germination. In contrast to ADH, the LDH isozymes present in developing seeds are similar to those found in uninduced and induced roots. Developmental expression of ADH and LDH was monitored from 0 to 24 days postgermination. Neither activity was induced to any extent in the germinating seeds; however, both enzymes were highly induced by anoxia in root tissue during development. Based on gel electrophoresis, this increase in activity results from the differential expression of different Adh and Ldh genes in root tissue. The changes in ADH and LDH activity levels were matched by changes in the amount of these particular proteins, indicating that the increase in activity results from de novo synthesis of these two proteins. The level of inducible LDH activity in an ADH1(-) mutant was not found to differ from cv Himalaya. We suggest that although the ADH(-) plants are more susceptible to flooding, they are not capable of responding to the lack of ADH1 activity by increasing the amount of LDH activity in root tissue.

Journal Article↗
PubMed1986

Regulation of glycerol phosphate dehydrogenase and lactate dehydrogenase activity by forskolin and dibutyryl cyclic AMP in the C6 glial cells.

We have compared the effects of norepinephrine, forskolin, and dibutyryl cyclic AMP (Bt2cAMP) on the regulation of the cytosolic enzyme glycerol phosphate dehydrogenase (GPDH) in the C6 rat glioma cell line. Forskolin and Bt2cAMP elicit a dose-dependent increase in the levels of the enzyme that was, however, unaffected by norepinephrine. The half-maximal effect of forskolin was obtained at 7-8 microM, and the effect was maximal at 30 microM. Dexamethasone at a 50 nM concentration produced a two- to sixfold induction of GPDH after 48 h. The combination of dexamethasone with forskolin or Bt2cAMP leads to an elevation in GPDH levels that is higher than that produced by one of the compounds alone. This potentiation is found when both agents are added together with or after the glucocorticoid. The increase in uninduced and dexamethasone-induced GPDH activity was blocked by cycloheximide and actinomycin D, indicating that de novo protein and RNA synthesis are required. The activity of cytosolic lactate dehydrogenase activity did not change after incubation with dexamethasone, but increased with forskolin or Bt2cAMP.

Animals↗
PubMed1991

A synthesis of acylphosphonic acids and of 1-aminoalkylphosphonic acids: the action of pyruvate dehydrogenase and lactate dehydrogenase on acetylphosphonic acid.

Acylphosphonic acids, R-CO-PO(OH)2, have been synthesized by the steps [formula: see text] of which the last is new and provides a mild method for de-esterifying acylphosphonic acids. Their reductive amination gives a simple way of making 1-aminoalkylphosphonic acids. Acetylphosphonic acid inhibited NAD+ reduction by pyruvate with the pyruvate dehydrogenases from Escherichia coli and Bacillus stearothermophilus. The inhibition was competitive with pyruvate, with Ki of 6 microM for the E. coli enzyme (pyruvate Km 0.5 mM) and one of 0.4 mM of the B. stearothermophilus enzyme (pyruvate Km 0.1 mM). Acetylphosphonate and its monomethyl ester are substates for pig heart lactate dehydrogenase, with Km values of 15 mM and 10 mM respectively (pyruvate Km 0.05 mM) and specificity constants one thousandth that for pyruvate.

Acetaldehyde↗
PubMed1987

The reduction of aromatic alpha-keto acids by cytoplasmic malate dehydrogenase and lactate dehydrogenase.

This study demonstrates that cytoplasmic malate dehydrogenase (MDH-s) catalyzes the reduction of aromatic alpha-keto acids in the presence of NADH, that the enzyme which has been described in the literature as aromatic alpha-keto acid reductase (KAR; EC 1.1.1.96) is identical to MDH-s, and that the reduction of aromatic alpha-keto acids is due predominantly to a previously unrecognized secondary activity of MDH-s and the remainder is due to the previously recognized activity of lactate dehydrogenase (LDH) toward aromatic keto-acids. MDH-s and KAR have the same molecular weight, subunit structure, and tissue distribution. Starch gel electrophoresis followed by histochemical staining using either p-hydroxy-phenylpyruvic acid (HPPA) or malate as the substrate shows that KAR activity comigrates with MDH-s in all species studied except some marine species. Inhibition with malate, the end product of the MDH reaction, substantially reduces or totally eliminates KAR activity. Genetically determined electrophoretic variants of MDH-s seen in the fresh water bony fish of the genus Xiphophorus and the amphibian Rana pipiens exhibited identical variation for KAR, and the two traits cosegregated in the offspring from one R. pipiens heterozygote studied. Both enzymes comigrate with no electrophoretic variation among several inbred strains of mice. Antisera raised against purified chicken MDH-s totally inhibited both MDH-s and KAR activity in chicken liver homogenates. There is no evidence to suggest that any protein besides MDH-s and LDH catalyzes this reaction with the possible exception of the situation in Xiphophorus, in which a third independent zone of HPPA reduction is observed. In most species the activity formerly described as KAR appears to be due to a previously unsuspected activity of MDH-s toward aromatic monocarboxylic alpha-keto acids. In all species examined the KAR activity is associated only with MDH-s; in tissue homogenates the mitochondrial form of MDH (MDH-m) is not detected after electrophoresis using HPPA as a substrate.

Amphibians↗
PubMed1998

Epoxyethane-/ethynesulfonamides with antifilarial activities. Degradation kinetics and inhibitory effect on filarial malate dehydrogenase and lactate dehydrogenase.

Some epoxyethane-/ethynesulfonamides had shown strong filaricidal activity with inconstant reproducibility as a result of a lack of stability in aqueous solution. The degradation in hydroxylic and aprotic solutions of two epoxyethanesulfonamides and one ethynesulfonamide was investigated using TLC, HPLC, GC and mass spectrometry. For both epoxydes, the degradation rate followed first-order kinetics and was more rapid in hydroxylic than in aprotic solutions. The degradation increased with the temperature whereas it was not modified with and without light exposure. Four kinds of degradation products were found: the first one involved the oxidation of the epoxyde bond, the second the breaking of the N-S bond, the third a desulfonation product and the fourth was not identified. In contrast, the stability of ethynesulfonamide was better than those of epoxyethanesulfonamide. These results suggest that epoxyethanesulfonamides should be kept at +4 degrees C before being injected to animals during the study of biological activity. Since epoxyde compounds are known to have inhibitory effects on parasite energy metabolism enzymes, the compunds were evaluated on two major filarial enzymes: lactate dehydrogenase (LDH) and cytoplasmic malate dehydrogenase (MDH). Both epoxyethanesulfonamides showed only a slight inhibitory effect on filarial LDH and MDH confirming the evidence that the main mode of action of these compounds remains to discover. Moreover, ethynesulfonamide and the degradation products of both epoxyethane-sulfonamides had no effect on LDH and MDH.

Animals↗
PubMed1977

Optimal conditions for assaying human lactate dehydrogenase by the lactate-to-pyruvate reaction: Arrhenium relationships for lactate dehydrogenase isoenzymes 1 and 5.

Optimal reaction conditions to sassay human lactate dehydrogenase (lactate-to-pyruvate) were established for isoenzymes 1 and 5 at 25, 30, and 37 degrees C in diethanolamine and 2-amino-2-methyl-1,3-propanediol. Different substrate concentrations are required at each temperature. The conditions permit measurement of lactate dehydrogenase 1 and 5 with the lowest substrate concentrations that allow for the highest equal sustainable efficiency in measuring both isoenzymes. About 95% of each isoenzyme activity is measured if the assay is performed within the first minute after the reaction is initiated even for activities as high as triple the upper limit of normal. The Arrhenius relationship is different for each isoenzyme, but results obtained for each at one temperature can be compared with results at another temperature by use of simple conversion equations. Assays at 25 and 30 degrees C are more economical and less variable than assays at 37 degrees C.

Buffers↗