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PubMed1990

Effect of almond and anis oils on mouse liver alcohol dehydrogenase, aldehyde dehydrogenase and heart lactate dehydrogenase isoenzymes.

The effects of short-term intraperitoneal injection of diluted almond or anis oil on heart lactate dehydrogenase isoenzymes, liver alcohol dehydrogenase and subcellular aldehyde dehydrogenase were studied in the female mouse. Hepatic alcohol dehydrogenase was induced from control by administration of almond oil 3.2 g/kg/d for 7 days, or anis oil 1.6 g/kg/d for 7 days. Treatment with almond but not anis oil inhibited both cytoplasmic and mitochondrial liver aldehyde dehydrogenase. The mitochondrial isoenzyme with an apparently low Km was also inhibited by the almond oil trial. No significant changes occurred in heart lactate dehydrogenase isoenzymes by the treatments used. The enzymatic inhibition kinetics were found to be non-competitive. The apparent Km for almond-treated mouse aldehyde dehydrogenase was greater than the controls. This indicates lower substrate affinity for almond oil than for acetaldehyde. The results suggest adverse hepatic metabolic interaction between almond oil and alcohol.

Alcohol Dehydrogenase↗
PubMed1976

Changes in lactate dehydrogenase, LDH isoenzymes, lactate, and pyruvate as a result of feeding low fat diets to healthy men and women.

A study was conducted to evaluate the effects on blood lipids and lipoproteins of feeding 21 healthy volunteers, 40-60 yr old, foods commonly eaten in the United States for two 40-day periods. Activities of lactate dehydrogenase (LDH) and LDH isoenzymes, lactate, and pyruvate were monitored. Results showed that LDH activity was significantly lower in all subjects at the end of the 25% fat-calorie period (period I) than at the beginning of the study, but rose above initial levels at the end of the 35% fat-calorie period (period II). While total LDH fell during period I, relative activity of M type subunits of LDH rose significantly in relation to H type in both sexes. This rise is probably indicative of an increase in glycolytic activity as a consequence of the increased intake of dietary carbohydrate. In period I, lactate and pyruvate decreased significantly in males (pyruvate greater than lactate) but not in females. Values for males returned to near initial levels in period II. The ratio of lactate/pyruvate was elevated in both sexes after period I. The greater change in pyruvate relative to lactate with increased dietary carbohydrate suggests increased Krebs Cycle activity. There was a statistically significant positive correlation between lactate, pyruvate, and serum triglyceride for males after they ate the 25% and 35% fat-calorie diets and for females after they ate the 35% fat-calorie diet, but not between lactate, pyruvate, and serum cholesterol for either sex.

Adult↗
PubMed1999

Classification and identification of strains of Lactobacillus brevis based on electrophoretic characterization of D-lactate dehydrogenase: relationship between D-lactate dehydrogenase and beer-spoilage ability.

The cell-free extracts of 60 strains which were identified phenotypically as being those of Lactobacillus brevis, including 48 isolates from the environment and 12 reference strains, were applied to polyacrylamide gel electrophoresis for extracting their NAD-dependent D- and L-lactate dehydrogenases (LDH). These strains were divided into 5 groups, i.e., Groups A, B, C, D, and E, on the basis of the electrophoretic mobilities of their D-LDH. The strains showed variations in their carbohydrate fermentation patterns. No relationship between the profile of D-LDH and the carbohydrate fermentation pattern was recognized. However, there appeared to be a relationship between the D-LDH profile and the beer-spoilage ability, because 40 out of 44 beer-spoilage strains identified as L. brevis were classified to Group B. We purified D-LDHs from the so-called complete beer-spoilage strain SBC 8002 of LDH Group B and from the non beer-spoilage strains JCM 1059T of LDH Group A and AHU 1508 of LDH Group C. Although the purified D-LDHs had the same molecular weight (84 kDa), each possessed a different optimum pH, optimum temperature, and isoelectric point. The aforementioned parameter values for the enzyme from the so-called complete beer-spoilage strain SBC 8002 of LDH Group B were 10.0, 50 degrees C, and 4.1, respectively; this strain was discriminated from the D-LDHs of the other two non beer-spoilage strains especially by its optimum temperature (50 degrees C).

Journal Article↗
PubMed1991

D-lactate dehydrogenase is a member of the D-isomer-specific 2-hydroxyacid dehydrogenase family. Cloning, sequencing, and expression in Escherichia coli of the D-lactate dehydrogenase gene of Lactobacillus plantarum.

The gene encoding D-lactate dehydrogenase (D-lactate: NAD+ oxidoreductase, EC 1.1.1.28) of Lactobacillus plantarum has been sequenced, and expressed in Escherichia coli cells with an inducible expression plasmid, in which the 5'-noncoding region of the gene was replaced with the tac promoter. Comparison of the sequence of D-lactate dehydrogenase with L-lactate dehydrogenases, including the L. plantarum L-lactate dehydrogenase, showed no significant homology. In contrast, the D-lactate dehydrogenase is homologous to E. coli D-3-phosphoglycerate dehydrogenase and Lactobacillus casei D-2-hydroxyisocaproate dehydrogenase. This indicates that D-lactate dehydrogenase is a member of a new family of 2-hydroxyacid dehydrogenases recently proposed, being distinct from L-lactate dehydrogenase and L-malate dehydrogenase, and strongly suggests that the new family consists of D-isomer-stereospecific enzymes. In the reductive reaction, the enzyme showed a broad substrate specificity, although pyruvate was the most favorable of all 2-ketocarboxylic acids tested. In particular, hydroxypyruvate is effectively reduced by the enzyme, the reaction rate, and Km value being comparable to those in the case of pyruvate, indicating that the enzyme has not only D-lactate dehydrogenase activity but also D-glycerate dehydrogenase activity. The conserved residues in this family appear to be the residues involved in the substrate binding and the catalytic reaction, and thus to be targets for site-directed mutagenesis.

Alcohol Oxidoreductases↗
PubMed1965

Organ specificity and lactate-dehydrogenase activity. Some properties of human spermatozoal lactate dehydrogenase.

1. The presence of a characteristic lactate-dehydrogenase isoenzyme (LD(x)) in human, mouse and dog testis and in human spermatozoa has been confirmed by electrophoresis on cellulose acetate and on polyacrylamide gel. 2. The human spermatozoal isoenzyme exhibits a much higher affinity for 2-oxobutyrate than any of the five isoenzymes found in other tissues. K(m) values of 0.05mm for pyruvate and 0.18mm for 2-oxobutyrate were obtained. 3. LD(x) differs from other lactate-dehydrogenase isoenzymes in that its properties cannot be correlated with its electrophoretic mobility. It resembles LD(1) in being strongly inhibited by 0.2mm-oxalate and relatively resistant to 2m-urea, and in being relatively stable to heat. 4. The surprisingly high activity of LD(x) with 2-oxobutyrate suggests that this substance or 2-hydroxybutyrate may play a part in spermatozoal metabolism.

Animals↗
PubMedDate not supplied

Measurement of total lactate dehydrogenase activity.

Lactate dehydrogenase (LD: EC 1.1.1.27) is the most important clinically of several dehydrogenases occurring in human serum. Lactate dehydrogenase is cytoplasmic in its cellular location and in any one tissue is composed of one or two of five possible isoenzymes. While many of its clinical applications involve quantification of one or more specific serum isoenzymes, an estimate of total LD is required usually. Lactate dehydrogenase catalyzes the reversible reaction: L-lactate + NAD+ in equilibrium pyruvate + NADH. The bidirectional reaction is monitored spectrophotometrically by measuring either the increase in NADH at 340 nm produced in the lactate-to-pyruvate reaction (L----P) or by the decrease in NADH at 340 nm produced in the pyruvate-to-lactate (P----L) reaction. Kinetic assay systems for the measurement of the reaction system in both directions are comprehensively reviewed as well as the standardization efforts proposed to date.

Enzyme Activation↗
PubMed1980

Cyclic AMP regulation of lactate dehydrogenase. Isoproterenol and N6,O2'-dibutyryl cyclic AMP increase the levels of lactate dehydrogenase-5 isozyme and its messenger RNA in rat C6 glioma cells.

The mechanism of isoproterenol and N6,O2'-dibutyryl adenosine 3':5'-monophosphate (dibutyryl cAMP) induction of lactate dehydrogenase (EC 1.1.1.27) was investigated in the C6 rat glioma cell line. [3H]Leucine-labeled lactate dehydrogenase in noninduced and induced cells was quantitatively immunoprecipitated with rabbit anti-rat lactate dehydrogenase-5 antiserum. The immunoprecipitates were analyzed for 3H-labeled lactate dehydrogenase by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels and isoelectrofocusing. Using this technique, it was shown that isoproterenol + 3-isobutyl-1-methylxanthine and dibutyryl cAMP cause an increase of the [3H]leucine incorporation into glioma cell lactate dehydrogenase. Analysis of the kinetics of induction and deinduction revealed no change in the rate of degradation of lactate dehydrogenase in the presence and absence of inducing agent, indicating that the induction was due to an increase in the rate of synthesis of the enzyme. The increased rate of synthesis was prevented by actinomycin D. Isoproterenol + 3-isobutyl-1-methylxanthine increased only the specific rate of synthesis of lactate dehydrogenase-5 isozyme and of the M subunit. The mechanism was further studied by assaying the level of functional mRNA coding for lactate dehydrogenase in a reticulocyte cell-free protein-synthesizing system using glioma cell poly(A)-containing RNA isolated from either isoproterenol or dibutyryl cAMP-induced cells. Analysis of the immunoprecipitated translation product by isoelectrofocusing revealed that isoproterenol or dibutyryl cAMP produced an approximately 8-fold stimulation of the poly(A) + RNA-directed synthesis of the lactate dehydrogenase M subunit. These data demonstrate that isoproterenol and dibutyryl cAMP control the level of functionally active lactate dehydrogenase mRNA in glioma cells which, in turn, determines the extent of synthesis of the lactate dehydrogenase M subunit.

1-Methyl-3-isobutylxanthine↗
PubMed1988

Reexamination of the kinetics of the transfer of NADH between its complexes with glycerol-3-phosphate dehydrogenase and with lactate dehydrogenase.

Srivastava and Bernhard [Srivastava, D. K. & Bernhard, S. A. (1986) Science 234, 1081-1086] have proposed that glycolytic enzymes form multienzyme complexes for the direct transfer of metabolites from the producing enzyme to the utilizing one. We have reinvestigated the evidence for direct transfer of NADH between its complexes with alpha-glycerol-3-phosphate dehydrogenase (GPDH; EC 1.1.1.8) and L-lactate dehydrogenase (LDH; EC 1.1.1.27). The results reveal the following. (i) Proper treatment of the kinetics of and equilibrium data for the transfer of NADH between GPDH and LDH indicates that NADH transfer proceeds by a free-diffusion mechanism and not by direct transfer through a ternary complex. (ii) The koff for NADH from its GPDH complex is 60 sec-1 rather than 9.4 sec-1 in Tris.HCl buffer (pH 7.4) at 25 degrees C. With this value one can explain kcat = 50 sec-1 for LDH-catalyzed hydrogenation of pyruvate with GPDH-bound NADH as coenzyme. (iii) Steady-state kinetics show that LDH inhibits the GPDH-catalyzed reaction simply by reducing the concentration of free NADH. Similarly, aldolase inhibits the GPDH-catalyzed reduction of dihydroxyacetone phosphate to glycerol-3-phosphate by binding to the substrate. The proposed direct transfer of NADH between GPDH and LDH is therefore mainly based on a misinterpretation of the experimental data.

Animals↗
PubMed1991

Hereditary lactate dehydrogenase M-subunit deficiency: lactate dehydrogenase activity in skin lesions and in hair follicles.

A 16-year-old Japanese girl had desquamating erythematosquamous lesions mostly on the extensor surface of the extremities. The lesions were worse in summer. The patient also had a mild muscle pain after strenuous exercise. Her paternal and maternal grandfathers are cousins. An analysis of lactic acid dehydrogenase (LDH) isozymes in her serum revealed a single peak of LDH1. Analysis of LDH isozymes of erythrocytes demonstrated a complete lack of LDH M-subunit in the patient and a substantial lack in the parents. The epidermis of the diseased skin and scalp hair follicles of the patient were virtually devoid of LDH activity.

Adolescent↗
PubMedDate not supplied

[pH-dependence of the structural and functional properties of lactate dehydrogenase (M4). Indirect cooperativity in lactate dehydrogenase].

The dependence of structural and functional properties of LDH on pH in the 6.0--9.0 region was investigated. There were no marked deviations of pyruvate reduction initial velocity curves from the Michaelis--Menten equation in a wide range of pyruvate concentrations. It was shown that Vmax changes negligibly in the 6.0--9.0 pH regions, but Km increased markedly with pH elevation. The pK value of 7.8+/-0.1 was obtained for 50% changes of pyruvate binding. The dependence of enzyme inhibition from pH at a high pyruvate concentration (20 mM) was investigated. At pH values above 8.0 pyruvate inhibition disappeared. The dependence of the inhibition degree from pH was estimated as pK 7.8+/-0.1. Hill coefficient (n) calculated from the curves of Km and the degree of substrate inhibition depending on pH was 1.6; n for pyruvate inhibition at pH 7.5 was 2 greater than n greater than 1 for moderate substrate concentrations (1--5 mM) and n approximately 1 for higher concentrations (5--40 mM). The value of n approximately 1 at pH 7.8 was obtained. The model suiting all available data concerning the cooperativity phenomena in LDH during protonation and inhibition by pyruvate is outlined. The model is based on the results indicating the slow isomerisation of LDH in ternary complexes with NADH and pyruvate and the absence of equilibrium on the intermediate stage of reaction.

Animals↗
PubMed1989

Use of purified lyophilized human lactate dehydrogenase isoenzyme 5 in a study of measuring lactate dehydrogenase activity.

We examined the stability of human lactate dehydrogenase (EC 1.1.1.27) isoenzyme 5--purified to a specific activity of about 400 kU/g--when lyophilized in a buffered, stabilized matrix of bovine albumin. This isoenzyme was prepared with a final activity of about 500 U/L and stored at -20, 4, 20, 37, and 56 degrees C for as long as six months. This isoenzyme decayed with approximate first-order kinetics, with an estimated half-life at -20 degrees C of about 475 years. Stability of reconstituted samples stored at 20 or 4 degrees C was poor, suggesting that the reconstituted material should be used without delay; material stored at -20 degrees C showed excellent stability for 15 days. We propose that such preparations might be further investigated as standards for use in electrophoresis of lactate dehydrogenase isoenzymes.

Enzyme Stability↗
PubMedDate not supplied

[Protein fractions of the ova, embryos and skeletal muscles of the loach affecting the stability and activity of lactate dehydrogenase].

When lactate dehydrogenase obtained from Misgurnus muscles and purified to the homogeneous state is incubated for 16 hat 38 degrees C, its activity lowers down to 10% of the initial value. Extracts of egg cells, embryos or skeletal muscles of the mentioned fish species added to the enzyme solution decrease considerably its inactivation. Proteins stabilizing the activity of lactate dehydrogenase are revealed in the supernatant liquid obtained after salting out of the above extracts with 60% sulphate ammonium saturation. These proteins are in fractions with the molecular weight below 45 kDa. Among proteins with the molecular weight 10 kDa there are polypeptides which exert an activation effect on lactate dehydrogenase. This effect is intensified with the presence of insulin.

Animals↗
PubMed1975

New instrument for rapid determination of activities of lactate dehydrogenase isoenzymes.

Lactate dehydrogenase isoenzymes can be distinguished kinetically by the fact that isoenzyme H is strongly inhibited a few seconds after the reaction is started if high concentrations of pyruvate are present, in contrast to the M isoenzyme. A new instrument that exploits this fact can measure both the total activity and the proportion of H isoenzyme in serum or plasma in 8 to 10 s. The instrument consists of a simplified stopped-flow apparatus in which the plasma is assayed for lactate dehydrogenase activity, and an electronic device that measures the rate of the reaction at two pre-set time intervals. The first rate is taken between 0.2 and 0.4 s after the reaction is started, a time at which both isoenzymes are fully active, and at which the rate obtained thus reflects total lactate dehydrogenase activity in the plasma sample. The second rate is measured 4 to 6 s after the start of the reaction, at which time the H isoenzyme has become inhibited and the observed rate compared to the initial rate is therefore proportional to the percentage of H isoenzyme activity in the serum. These two rates are electronically displayed on two three-digit voltmeters, the first display being the total activity, the second a number proportional to the inhibited slope. The percentage of M isoenzyme can then be calculated from the initial and final rate. A total of five to six repeat assays may be done within a minute on 1 ml of plasma or serum. This instrument may be of significant value in following the progress of myocardial infarctions and other diseases.

Autoanalysis↗
PubMed1981

Comparison of three serum alpha-hydroxybutyrate dehydrogenase procedures for lactate dehydrogenase isoenzyme discrimination.

Three recently proposed methods for the assay of alpha-hydroxybutyrate (2-oxobutyrate) dehydrogenase (HBD) activity in serum were assessed to determine which one would give the most useful discrimination between the lactate dehydrogenase (LD) isoenzymes. The 2-oxobutyrate concentration and temperature for these procedures were 3.3 mmol/l at 30 degree C, 12 mmol/l at 30 degree C and 15 mmol/l at 37 degree C. LD isoenzyme activity values obtained by thin-layer agarose electrophoresis were compared with HBD activity results by linear regression analysis. The best, statistically significant, correlation of LD-1 with HBD activities was obtained with 3.3 mmol/l at 30 degree C (regression coefficient, 0.92; correlation coefficient, 0.98).

Electrophoresis, Agar Gel↗