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PubMedDate not supplied

C-reactive protein and lactate dehydrogenase isoenzymes in the assessment of the prognosis of acute pancreatitis.

The value of serum C-reactive protein, lactate dehydrogenase isoenzymes and erythrocyte sedimentation rate in predicting the outcome of acute pancreatitis was evaluated for 57 episodes in 54 patients. Serum C-reactive protein levels on day 2, 4 and 7 after admission were significantly higher in 19 episodes of severe attacks than in 38 episodes of mild attacks (13.71 +/- 9.68, 9.00 +/- 7.54, 6.02 +/- 3.83 vs 4.78 +/- 3.91, 3.30 +/- 3.61, 1.43 +/- 2.08 mg/dL; P less than 0.0001, P less than 0.005, P less than 0.0001, respectively). The sensitivity, specificity and accuracy of predicting a severe attack were 94, 76 and 82% using C-reactive protein greater than or equal to 8 mg/dL on day 2; 67, 92 and 84% using C-reactive protein greater than or equal to 5 mg/dL on day 7; and 59, 76 and 70% using Ranson's criteria greater than or equal to 3. Increases in LDH-4 and LDH-5 isoenzymes were found in both groups, with LDH-4 being slightly higher in severe attacks than in mild attacks. There was no significant difference of erythrocyte sedimentation rate between both groups. When compared with Ranson's criteria, lactate dehydrogenase isoenzymes and erythrocyte sedimentation rate, C-reactive protein is more valuable in the early assessment of the severity of acute pancreatitis.

Acute Disease↗
PubMed1983

Thermodynamic studies of the activation of rabbit muscle lactate dehydrogenase by phosphate.

In an attempt to trace the source of phosphate activation of the enzyme-catalysed pyruvate-lactate interconversion by rabbit muscle lactate dehydrogenase, equilibrium constants were measured to examine the effects of phosphate on interactions pertinent to the enzymic process. Frontal gel-chromatographic studies of the binding of NADH to the enzyme established that the intrinsic association constant is doubled in the presence of 50 mM-phosphate in the buffer (pH 7.4, I0.15). From kinetic studies of the competition between NAD+ and NADH for the coenzyme-binding sites of the enzyme it is concluded that the binding of oxidized nicotinamide nucleotide is also doubled in the presence of 50 mM-phosphate. Competitive-inhibition studies and fluorescence-quenching measurements indicated the lack of a phosphate effect on ternary-complex formation between enzyme-NADH complex and oxamate, a substrate analogue of pyruvate. The equilibrium constant for the interaction between enzyme-NAD+ complex and oxalate, an analogue of lactate, was also shown, by difference spectroscopy, to be insensitive to phosphate concentration. Provided that the effects observed with the substrate analogues mimic those operative in the kinetic situation, the equilibrium constant governing the isomerization of ternary complex is also independent of phosphate concentration. It is concluded that enhanced coenzyme binding is the source of phosphate activation of the rabbit muscle lactate dehydrogenase system.

Animals↗
PubMedDate not supplied

[Lactate dehydrogenase isoenzymatic makeup of the skeletal muscles of rats after a flight on the Kosmos-690 biosatellite].

The isoenzyme composition of lactate dehydrogenase in the soleus and plantaris muscles of rats which had flown for 20.5 days onboard the biosatellite Cosmos-690 equipped with a radiation source was studied. Difference in the isoenzyme composition of lactate dehydrogenase in flight and synchronous rats disappeared 27 days after the experiments; however, some changes persisted as compared with vivarium controls. The data obtained give evidence that irradiation-induced effects in skeletal muscles manifested themselves at a far later stage than weightlessness-induced changes.

Animals↗
PubMed1993

Increased expression of the lactate dehydrogenase M subunit in myocardial regions with decreased thallium uptake.

OBJECTIVE: In ischaemic heart disease, the heart muscle is subjected to repeated episodes of regional ischaemia or to a constant underperfusion. The purpose of the present investigation was to study the myocardial metabolic adaptation to this stress. METHODS: Eighteen male patients with ischaemic heart disease were studied by biopsies taken from the left ventricular septum during bypass surgery. Citrate synthase, total lactate dehydrogenase and its H and M subunits, coenzyme Q10, and myoglobin were determined in all biopsies. Concentrations of ATP, ADP, and AMP were determined and energy charge calculated in the biopsies from the patients with ischaemic heart disease. Biopsies from the septal region of hearts obtained from brain dead kidney and liver donors were used as reference and preoperative myocardial thallium scintigraphy was performed in the patients with ischaemic heart disease to relate the myocardial biochemical markers to thallium uptake at the biopsy site. RESULTS: Myocardial activities of citrate synthase as well as contents of coenzyme Q10 and myoglobin in patients with ischaemic heart disease were not different from those of the reference group, and no linear relation was found between these three markers on the one hand and thallium uptake on the other. The energy charge was directly related and the M subunit of lactate dehydrogenase inversely related to the thallium uptake. CONCLUSION: The results suggest an absence of adaptation to ischaemia in terms of increased myocardial oxidative capacity and O2 transport and storage capacity. Furthermore, it is indicated that a stressed energy metabolism with increasing severity of ischaemic heart disease enhances anaerobic metabolism and induces a shift in myocardial lactate dehydrogenase subunit fractions.

Adolescent↗
PubMed1998

Transient abnormalities in serum bilirubin and lactate dehydrogenase levels following red blood cell transfusions in adults.

BACKGROUND: The effect of transfusion of small amounts of packed red blood cells (PRBC) on serum chemistry values is not known. METHODS: We studied 73 adult patients without evidence of bleeding who received 2-unit PRBC transfusions. In study 1 (n=39), we examined multiple laboratory values pretransfusion and 15 minutes, 1 hour, 2 hours, and 24 hours posttransfusion. In study 2 (n=34), we examined changes in fractionated bilirubin, lactate dehydrogenase, and haptoglobin prior to and 1 hour following the transfusion. RESULTS: Total bilirubin increased from a median pretransfusion baseline of 0.7 mg/dL to 1.4 mg/dL shortly after transfusion (P <0.0005), and then returned to normal 24 hours later. Of the 36 patients with normal pretreatment total bilirubin levels, 17 (47%) became transiently abnormal. The lactate dehydrogenase level increased similarly 15 minutes after transfusion, but returned to baseline 24 hours later. The unconjugated bilirubin level increased from a median baseline pretransfusion value of 0.3 mg/dL to 1.1 mg/dL at 1 hour posttransfusion (P <0.0005). No significant changes were noted in conjugated bilirubin levels or haptoglobin concentration following transfusion. CONCLUSIONS: Transient increases in serum bilirubin and lactate dehydrogenase are seen following transfusion of PRBC. These data should be considered when interpreting laboratory values during the first few hours after a transfusion.

Adult↗
PubMed1979

The nature of the substrate inhibition in lactate dehydrogenases as studied by a spin-labeled derivative of NAD.

The formation of the ternary complex of lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) from pig heart and skeletal muscle with the adduct of pyruvate to NAD", spin-labeled at N6 was studied by ultraviolet spectroscopy and ESR techniques. According to ultraviolet measurements we found identical binding characteristics for the natural coenzyme and its spin-labeled analog. The rate by which the ESR signal of free spin-labeled NAD+ decreased upon addition of pyruvate to the binary complexes was substantially different in the two isozymes. With the heart type an initial drop followed by a further linear decrease, zero order in the enzyme and coenzyme concentration was observed. In case of the skeletal muscle isozyme no immediate reaction and a first order process occurred. The initial reaction can be attributed to a non-covalent enzyme/spin-labeled NAD+/pyruvate complex with a dissociation constant for pyruvate of 11 +/- 1 mM, thus explaining the well-known substrate inhibition in the heart isozyme above 2 mM pyruvate. The further reaction is then determined by the buffer dependent enolization of pyruvate. In the muscle isozyme formation of the covalent adduct is not assisted by prior binding of pyruvate in a non-covalent ternary complex and therefore the rate depends on the binary complex concentration.

Animals↗
PubMed1979

The binding of spin-labeled derivatives of NAD+ and its structural components to pig skeletal muscle lactate dehydrogenase.

The binding of spin-labeled derivatives of NAD+ and its structural components to pig skeletal muscle lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) is described. In contrast to results previously obtained with the heart muscle isozyme (Wenzel, H.R., Pfleiderer, G., Trommer, W.E., Paschenda, K. and Redhardt, A. (1976) Biochim. Biophys. Acta 452,292--301), no significant increase is observed in the binding constant of N6-SL-ADP as compared N6-SL-AMP. This different behavior can be explained by the substitution of glutamine-31 for alanine in the muscle isozyme, which has been proposed to account for the the tighter binding of NADH to the heart type. In both isozymes the binding of the binding of the spin-labeled coenzyme itself is weaker than found for its structural components.

Animals↗
PubMed2002

Crystallization and some properties of D-lactate dehydrogenase from Staphylococcus sp. LDH-1.

Staphylococcus sp. LDH-1 isolated as a high producer of lactate dehydrogenase grew well under anaerobic conditions and produced a large amount of D-lactate dehydrogenase (D-LDH), but not L-LDH. After purification of this D-LDH, some properties were revealed. The enzyme catalyzed the reversible reduction of 2-oxo acids into D-2-hydroxy acids, but not into L-2-hydroxy acids. The K(m) values for 2-oxo acids were much smaller than those for D-2-hydroxy acids, and the V(max) values for 2-oxo acids were much greater than those for D-2-hydroxy acids. The equilibrium constants for the reaction of the reductions of pyruvic acid to D-lactic acid and of 2-oxobutyric acid to D-2-hydroxy-n-butyric acid were 270 and 360, respectively. The enzyme was stable between pH 5.5 and 8.5, while the optimum pH for pyruvic acid and D-lactic acid was pH 5.0 and 8.2, respectively. It was therefore concluded that the D-LDH from Staphylococcus sp. LDH-1 is available as enzyme for an assay of pyruvic acid and for the production of D-2-hydroxy acids.

Journal Article↗
PubMed1987

Serum creatine kinase and lactate dehydrogenase isoenzyme levels in patients after major esophageal surgery, esophageal dilation, and acute myocardial infarction.

All three isoenzymes of creatine kinase (CK), including MB, the fraction used in diagnosing acute myocardial infarction (AMI), have been found in the esophagus. Clinical reports suggest that injuries to the esophagus can cause changes in peripheral serum CK. This prospective study was designed to delineate whether esophageal dilation or major esophageal surgery would cause changes in serum CK and lactate dehydrogenase isoenzymes that might be consistent with the diagnosis of an AMI. Two groups of patients admitted to a coronary care unit were used as controls: patients with electrocardiographically proved AMI and those who had chest pain but who had AMI ruled out by sequential electrocardiograms. The coronary care unit patients had serum enzymes determined on admission, then every 8 hours for four samples, and then daily for 3 days. The surgical patients had determinations preoperatively, in recovery, every 8 hours for four samples, and daily for 5 days. The patients who had esophageal dilations had serum enzyme levels drawn before the procedure and every 8 hours for 2 days after dilation. Serum total CK and lactate dehydrogenase levels were determined by automated spectrophotometry. Isoenzyme levels were determined by agarose gel electrophoresis. The data suggest that small serum CK-MB bands that may be generated by esophageal surgery or dilation can be differentiated from those seen in AMI and that AMI can be confirmed by simultaneous analysis of serum lactate dehydrogenase isoenzymes.

Clinical Enzyme Tests↗
PubMed1983

Micromethod for determination of lactate dehydrogenase isoenzyme C4 activity in human seminal plasma.

We have developed an automated enzymatic assay for LDH-C4, a lactate dehydrogenase (EC 1.1.1.27) isoenzyme found exclusively in spermatozoa, as a marker of human spermatogenesis. LDH-C4 activity is assayed bichromatically in the Abbott ABA-100 spectrophotometer, with 2-oxohexanoate as substrate. As many as 27 samples (2.5 microL) of human seminal plasma can be analyzed sequentially, with apparent zero-order kinetic conditions and with a precision (CV) of 5%. The apparent Km for the 2-oxohexanoate reaction is 11.2 mmol/L. Electrophoretic and enzymatic studies indicate that LDH-C4 acts on this substrate to produce hydroxyhexanoate, in contrast to lactate dehydrogenase isoenzymes 1 and 5--further evidence for the uniqueness of LDH-C4. The sensitivity, specificity, and speed of this assay system makes it practicable for studies on, and evaluation of, male fertility.

Caproates↗
PubMed1992

Activity of serum creatine kinase, lactate dehydrogenase and LD isoenzymes in piglets affected with congenital tremor: a case report.

The activities of serum creatine kinase (CK), lactate dehydrogenase (LD) and LD isoenzymes were studied in 14 Prestice black pied pigs from a herd affected with congenital tremor. Mean CK activity was 19.57 +/- 3.56 mu kat.l-1 for 6 adult pigs, and it was 21.03 +/- 1.33 mu kat.l-1 and 20.42 +/- 1.23 mu kat.l-1 for the affected (n = 5) and control (n = 3) piglets, respectively. No significant differences were demonstrable between the groups in CK activity. Total serum LD and LD-4 as well as LD-5 isoenzyme activities were higher in sows. Piglets affected with congenital tremor showed an increase in total LD enzyme and LD-5 isoenzyme activity. It is concluded that no relationship exists between congenital tremor and serum CK activity in piglets. At the same time, there is a positive relationship between congenital tremor and significantly (P < 0.01) elevated LD enzyme and LD-5 isoenzyme activity. The results allow us to suggest that total lactate dehydrogenase and LD-5 isoenzyme activities could be used as biological markers of congenital tremor in piglets.

Animals↗
PubMed1991

Design and synthesis of new enzymes based on the lactate dehydrogenase framework.

Analysis of the mechanism and structure of lactate dehydrogenases is summarized in a map of the catalytic pathway. Chemical probes, single tryptophan residues inserted at specific sites and a crystal structure reveal slow movements of the protein framework that discriminate between closely related small substrates. Only small and correctly charged substrates allow the protein to engulf the substrate in an internal vacuole that is isolated from solvent protons, in which water is frozen and hydride transfer is rapid. The closed vacuole is very sensitive to the size and charge of the substrate and provides discrimination between small substrates that otherwise have too few functional groups to be distinguished at a solvated protein surface. This model was tested against its ability to successfully predict the design and synthesis of new enzymes such as L-hydroxyisocaproate dehydrogenase and fully active malate dehydrogenase. Solvent friction limits the rate of forming the vacuole and thus the maximum rate of catalysis.

Amino Acid Sequence↗
PubMed2006

Testis-specific lactate dehydrogenase (LDH-C4; Ldh3) in murine oocytes and preimplantation embryos.

LDH-C(4) (Ldh3) is a member of the lactate dehydrogenase family of isozymes that catalyze the terminal reaction in the glycolytic pathway. In mammals, 3 genes, ldha, ldhb, and Ldhc, encode the subunits that assemble into catalytically active homo- and heterotetramers. Differential expression of these genes determines the lactate dehydrogenase (LDH) isozyme composition of tissues, and, as is well known, A subunits predominate in skeletal muscle and B subunits are abundantly produced in brain and heart, with the Ldh2 isozyme the most abundant form in oocytes. The C peptide can be detected first in pachytene spermatocytes and constitutes the primary LDH of spermatozoa. Originally the Ldhc gene (Ldh3 in terminology applied to murine cells) was considered to be testis specific on the basis of immunochemical, enzymatic, and molecular analyses. Here we report the detection of this isozyme in the murine oocyte and early embryo. Our results indicate that Ldh3 mRNA is transcribed in oocytes and cannot be detected in fertilized eggs. Ldh3 protein, however, persists to the blastocyst stage of embryonic development localizing mainly to the cortex region of oocytes, eggs, zygotes, and embryonic blastomeres.

Amino Acid Sequence↗
PubMed1989

Catalytic properties of thermophilic lactate dehydrogenase and halophilic malate dehydrogenase at high temperature and low water activity.

Thermophilic lactate dehydrogenases from Thermotoga maritima and Bacillus stearothermophilus are stable up to temperature limits close to the optimum growth temperature of their parent organisms. Their catalytic properties are anomalous in that Km shows a drastic increase with increasing temperature. At low temperatures, the effect levels off. Extreme halophilic malate dehydrogenase from Halobacterium marismortui exhibits a similar anomaly. Increasing salt concentration (NaCl) leads to an optimum curve for Km, oxaloacctate while Km, NADH remains constant. Previous claims that the activity of halophilic malate dehydrogenase shows a maximum at 1.25 M NaCl are caused by limiting substrate concentration; at substrate saturation, specific activity of halophilic malate dehydrogenase reaches a constant value at ionic strengths I greater than or equal to 1 M. Non-halophilic (mitochondrial) malate dehydrogenase shows Km characteristics similar to those observed for the halophilic enzyme. The drastic decrease in specific activity of the mitochondrial enzyme at elevated salt concentrations is caused by the salt-induced increase in rigidity of the enzyme, rather than gross structural changes.

Catalysis↗
PubMed1986

Use of monoclonal antibodies to detect conformational alterations in lactate dehydrogenase isoenzyme 5 on heat denaturation and on adsorption to polystyrene plates.

A monoclonal antibody (mAb) MF30 (IgGl) against human lactate dehydrogenase isoenzyme 5 (HLDH5) was prepared. MF30 was found to bind with high specificity to HLDH5 when the enzyme was adsorbed onto a polystyrene plate but did not recognize the isoenzyme when in solution. The isoenzymes HLDH1, HLDH2 and HLDH3 adsorbed onto polystyrene were not recognized by mAb MF30. Heat-treated HLDH5 (heated at 70 degrees C, pH 7.5 for 45 sec) behaved towards MF30 in the same way as the untreated isoenzyme, i.e. interaction between them took place only after the denatured isoenzyme had been adsorbed onto an ELISA plate. A second mAb, designated 2/66, prepared against porcine lactate dehydrogenase isoenzyme 5 (PLDH5), was found to interact with the porcine isoenzyme when in solution as well as when adsorbed onto polystyrene. However, no such interaction occurred after the isoenzyme had been subjected to heat treatment as above. The mAb 2/66 was found to cross-react fully with the human isoenzyme HLDH5 both in solution and when adsorbed onto polystyrene; however, as in the case of the porcine isoenzyme, all such recognition was lost upon heat denaturation. The above findings suggest that the adsorption of HLDH5 onto a polystyrene surface is accompanied by a conformational change. Denaturation of the enzyme by heat seems to lead to the appearance of a conformation differing in its antigenic pattern from that of the adsorbed enzyme. The data suggest that the mAbs MF30 and 2/66 recognize two different antigenic sites of HLDH5. The antigenic site which is recognized by 2/66 and is present in the native enzyme both when in solution and when adsorbed onto polystyrene disappears on heating. The other antigenic determinant is recognized by mAb MF30 when the enzyme is adsorbed onto a polystyrene surface either before or after heat treatment. This study illustrates the way in which appropriate mAbs might possibly be used as probes for the detection of conformational alterations occurring in proteins under various conditions.

Adsorption↗
PubMed1978

[Lactate dehydrogenase. An example of the development of modern enzymology].

Lactate dehydrogenase is the prototype of an oligomeric, intracellular enzyme. Its primary, secondary, tertiary, and quaternary structures are now well known. This fact, especially with regard to the occurrence of isoenzymes, has effected a great progress in the understanding of the structure-function relationship of enzymes. The historical development of modern enzymology is described, together with discussions of the various methods and problems of enzymology.

Animals↗
PubMed1975

Regulation of lactate dehydrogenase and change of fermentation products in streptococci.

Streptococcus mutans JC 2 produced mainly lactate as a fermentation product when grown in nitrogen-limited continuous culture in the presence of an excess of glucose and produced formate, acetate, and ethanol, but no lactate, under glucose-limited conditions. The levels of lactate dehydrogenase (LDH) in these cultures were of the same order of magnitude, and the activity of LDH was completely dependent on fructose-1,6-diphosphate (FDP). The intracellular level of FDP was high and the level of phosphoenolpyruvate (PEP) was low under the glucose-excess conditions. In the glucose-limited cultures, all glycolytic intermediates studied, except PEP, were low. S. mutans FIL, which had an FDP-independent LDH and similar levels of glycolytic intermediates as S. mutans JC2, produced mainly lactate under glucose-excess or under glucose-limited conditions. LDH of Streptococcus bovis ATCC 9809 was dependent on FDP for activity at a low concentration of pyruvate but had a significant activity without FDP at a high concentration of pyruvate. This strain also produced mainly lactate both under glucose-excess and glucose-limited conditions. The levels and characteristics of these LDHs were not changed by the culture conditions. These results indicate that changes in the intracellular level of FDP regulate LDH activity, which in turn influences the type of fermentation products produced by streptococci. PEP, adenosine 5'-monophosphate, adenosine 5'-diphosphate, and inorganic phosphate significantly inhibited LDH activity from S. mutans JC 2 and may also participate in the regulation of LDH activity in other streptococci.

Acetates↗