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PubMed1987

Epitopes of human testis-specific lactate dehydrogenase deduced from a cDNA sequence.

The sequence and structure of human testis-specific L-lactate dehydrogenase [LDHC4, LDHX; (L)-lactate: NAD+ oxidoreductase, EC 1.1.1.27] has been derived from analysis of a complementary DNA (cDNA) clone comprising the complete protein coding region of the enzyme. From the deduced amino acid sequence, human LDHC4 is as different from rodent LDHC4 (73% homology) as it is from human LDHA4 (76% homology) and porcine LDHB4 (68% homology). Subunit homologies are consistent with the conclusion that the LDHC gene arose by at least two independent duplication events. Furthermore, the lower degree of homology between mouse and human LDHC4 and the appearance of this isozyme late in evolution suggests a higher rate of mutation in the mammalian LDHC genes than in the LDHA and -B genes. Comparison of exposed amino acid residues of discrete antigenic determinants of mouse and human LDHC4 reveals significant differences. Knowledge of the human LDHC4 sequence will help design human-specific peptides useful in the development of a contraceptive vaccine.

Amino Acid Sequence↗
PubMed1978

Isoenzyme distribution of creatine kinase and lactate dehydrogenase in serum and skeletal muscle in Duchenne muscular dystrophy, collagen disease, and other muscular disorders.

We determined the total activity and isoenzyme distribution of lactate dehydrogenase and creatine kinase in serum and biopsy specimens from skeletal muscle of nine normal individuals and nine patients with Duchenne muscular dystrophy (I), five with collagen disease (II), and four with non-progressive unclassified myopathy (III). Mean total serum creatine kinase in patients with Duchenne muscular dystrophy (867 U/liter, SD = 197) was 31-fold that in the control group (28 U/liter, SD = 14). There was also a small (3.3-fold) increase in the mean total serum creatine kinase of patients with III, but none in the serum from patients with II. Changes in the creatine kinase isoenzyme distribution of skeletal muscle were primarily in the MB isoenzyme. The mean percentage of creatine kinase-MB activity in muscle from patients with I (2.81, SD = 1.15) and patients with III (1.69, SD = 1.07) significantly (P less than 0.005) exceeded that of the control group (0.43, SD = 0.18). Muscle from patients with II showed little change. The most striking changes in lactate dehydrogenase were also observed in patients with I, in whom the mean total serum activity (356 U/liter, SD = 115) was 3.4-fold that of serum from the control group (105 U/liter, SD = 19). Skeletal muscle from these patients also showed a significant decrease in mean percent isoenzyme 5 activity (from 50 to 23) and an increase in that of isoenzymes 1 and 2 (from 1 to 9 and 8 to 20, respectively). These changes in the distribution of these two sets of isoenzymes in muscle were reflected in the serum.

Adolescent↗
PubMed2002

Crystal structure of non-allosteric L-lactate dehydrogenase from Lactobacillus pentosus at 2.3 A resolution: specific interactions at subunit interfaces.

L-Lactate dehydrogenase (LDH) from Lactobacillus pentosus is a non-allosteric enzyme, which shows, however, high sequence similarity to allosteric LDHs from certain bacteria. To elucidate the structural basis of the absence of allostery of L. pentosus LDH (LPLDH), we determined the crystal structure of LPLDH at 2.3 A resolution. Bacterial LDHs are tetrameric enzymes composed of identical subunits and exhibit 222 symmetry. The quaternary structure of LPLDH was similar to the active conformation of allosteric LDHs. Structural analysis revealed that the subunit interfaces of LPLDH are optimized mainly through hydrophilic interactions rather than hydrophobic interactions, compared with other LDHs. The subunit interfaces of LPLDH are more specifically stabilized by increased numbers of intersubunit salt bridges and hydrogen bonds, and higher geometrical complementarity. Such high specificity at the subunit interfaces should hinder the rearrangement of the quaternary structure needed for allosteric regulation and thus explain the "non-allostery" of LPLDH.

Allosteric Regulation↗
PubMed1998

Cellular source of serum lactate dehydrogenase elevation in patients with thrombotic thrombocytopenic purpura.

Elevated serum lactate dehydrogenase (LDH) is a characteristic finding in patients with thrombotic thrombocytopenic purpura (TTP). It is widely accepted that total serum LDH principally rises due to the release of red blood cell LDH as a consequence of intravascular hemolysis. To identify the cellular source of serum LDH in TTP, we prospectively analyzed total serum LDH and LDH isoenzyme profiles in 10 consecutive patients with classic, acute idiopathic TTP within 5 days of clinical presentation. Total LDH was quantitated on a Hitachi 911 Analyzer (Indianapolis, IN), using the lactate to pyruvate reaction. LDH isoenzymes were measured by serum protein electrophoresis, using the Beckman LDH Isoenzyme Kit (Anaheim, CA). Isoenzymes attributable to erythrocytes (LDH1, LDH2) were not disproportionately elevated in 9 of 10 patients. LDH3 was below or within normal limits for all 10 patients, and one patient showed a slightly increased LDH4. Serum LDH5, the isoenzyme derived primarily from liver and skeletal muscle, was elevated 1-2 times normal in all patients. Evidence supporting hemolysis as the major contribution to the elevated total serum LDH frequently encountered in acute TTP was not identified in this study. The isoenzyme fractions LDH and LDH2 elevated by erythrocyte injury were not disproportionately elevated in this series. LDH 5, the isoenzyme found in skeletal muscle and liver, was consistently 1- to 2-fold greater than normal in all patients. We propose that the elevation of serum LDH seen in patients with TTP is due to release of LDH from a variety of tissues damaged as a result of systemic ischemia.

Erythrocytes↗
PubMed1968

Lactate dehydrogenase isozymes: dissociation and denaturation by dilution.

The tetrameric enzyme lactate dehydrogenase dissociates into its constituent monomeric subunits in a high ion to protein concentration ratio, in certain ionic environments when frozen, and at extreme dilution. Dissociation by dilution involves changes in tertiary conformation which inactivate the enzyme. The dissociation is strongly inhibited by homologous native proteins, but only slightly by denatured or unrelated proteins.

Animals↗
PubMed2001

Analysis of arylsulfatases A and B, acid phosphatase, lactate dehydrogenase, and aspartate transaminase in chronic periapical lesions of endodontic origin.

Attempts were made to detect and measure the activities of arylsulfatases. A&B acid phosphatase, lactate dehydrogenase, and glutamate oxaloacetate transaminase (aspartate transaminase) enzymes in human chronic lesions of endodontic origin. Thirteen periapical lesions of endodontic origin and 11 noninflamed control periapical tissues were obtained. The specimens were carried to the laboratory on liquid nitrogen and kept at -70 degrees C. Samples were thawed, homogenized, and then assayed for enzyme activities. The specific activities of arylsulfatase A (nmol/hr/mg protein) were 55.0+/-10.7 (chronic lesions) vs. 3.4+/-2.2 (controls) (p < 0.01). Arylsulfatase B specific activities (nmol/hr/mg protein) were 50.3+/-6.4 (chronic lesions) vs 91.8+/-18.4 (controls). Total acid phosphatase activities (mU/mg protein) were 45.8+/-6.6 (chronic lesions) vs. 26.8+/-3.1 (controls). Lactate dehydrogenase activities (Berger-Broida units/mg protein) of the chronic periapical lesions were significantly higher than the control group (362+/-63.2) vs. (140+/-46.0) (p < 0.05). There was no significant difference between the specific activities of aspartate transaminase in chronic lesions and the control group (68.0+/-14.5) vs. (53.0+/-10.4) mU/mg protein).

Acid Phosphatase↗
PubMed1978

Membrane-bound, pyridine nucleotide-independent L-lactate dehydrogenase of Rhodopseudomonas sphaeroides.

Rhodopseudomonas sphaeroides has a pyridine nucleotide-independent L-lactate dehydrogenase associated with the membrane fraction of cells grown either aerobically or phototrophically. The dehydrogenase is present in cells grown on a variety of carbon sources, but at levels less than 20% of that found in cells grown with DL-lactate. The dehydrogenase has been purified 45-fold from membranes of strain L-57, a non-photosynthetic mutant, by steps involving solubilization with lauryl dimethylamine oxide and three anion-exchange chromatography steps. The purified enzyme was specific for the L-isomer of lactate. The Km of the purified enzyme for L-lactate is 1.4 mM, whereas that of the membrane-associated enzyme is 0.5 mM. The enzyme activity was inhibited competitively by D-lactate and non-competitively by oxalate and oxamate. Quinacrine, a flavin analog, also inhibited the activity. The inducible enzyme may serve as a marker of membrane protein in studies of membrane development.

Cell Membrane↗
PubMed1983

Isoenzymes of lactate dehydrogenase in amnionic fluid in early pregnancy.

Electrophoretic fractionation of lactate dehydrogenase in amnionic fluid was utilized to demonstrate the five isoenzymes usually found in a variety of human tissues. The anaerobic portion of the isoenzyme spectrum was prominent, and the percentage distribution may be related to the metabolic activities of tissues contributing to the formation of the fluid. In contrast to the placenta, an "extra" isoenzyme was not found in the fluid.

Adolescent↗
PubMed1977

The effect of storage and handling on the activity of lactate dehydrogenase and its isoenzymes in horse serum.

The activity of lactate dehydrogenase and its isoenzymes in normal horse serum was studied under four conditions of storage. For storage periods up to three weeks freezing (-20 degrees C) was most satisfactory whereas for 24 to 48 h room temperature proved optimal. The most unsuitable temperature for lengthy storage was 4 degrees C. Storage of clotted blood for up to 48 h may result in haemolysis and unexpected rise in activity.

Animals↗
PubMed2001

Alterations in myocardial creatinine kinase (CK) and lactate dehydrogenase (LDH) isoenzyme-distribution in a model of left ventricular dysfunction.

The purpose of the current study was to evaluate myocardial creatinine kinase (CK) and lactate dehydrogenase (LDH) systems in a model of epinephrine-induced cardiomyopathy in rabbits. Eight rabbits received four repetitive epinephrine infusions (300 mg/kg/60 min, i.v.) in 12-day intervals and eight untreated rabbits served as controls (CTRL). Echocardiography demonstrated a significant deterioration of LV function as well as increased LV-diameter and -mass index in catecholamine-induced cardiomyopathy. Histological examination revealed that repetitive catecholamine infusion resulted in LV fibrous areas with collagenous content and an increase in myocyte width (16.9+/-0.8 microm vs. CTRL 12.9+/-0.9; P<0.05). LV dysfunction was associated with a decreased total LV lactate dehydrogenase activity (LDH; 0.43+/-0.03 IU/mg protein vs. CTRL 0.52+/-0.04; P<0.05) whereas total creatinine kinase activity was unchanged (CK; 7.30+/-0.63 IU/mg protein vs. CTRL 9.20+/-0.49, n.s.). Furthermore, myocardial LDH isoenzymes were shifted with a decrease in LDH(1) and an increase in LDH2 and LDH3 (LDH(1): 84.90+/-2.60% vs. CTRL 94.50+/-0.40; LDH2: 7.30+/-1.20% vs. 1.50+/-0.13; LDH3: 5.40+/-0.90% vs. 3.20+/-0.25; all P<0.05). Foetal B-CK isoenzymes were significantly increased (CK-MB 5.30+/-0.66 vs. 2.20+/-0.35%; P<0.05). The current study demonstrates changes in cardiac energy metabolism including an impaired LDH activity with a shift towards anaerobic isoenzymes as well as a more efficient CK system in a model of catecholamine-induced LV dysfunction.

Animals↗
PubMed2004

[Cloning and function analysis of L-lactate dehydrogenase gene from Lactobacillus sp. MD-1].

It was constructed that a genomic DNA library from Lactobacillus sp. MD-1 yielding D, L-lactic acid. The gene encoding L-lactate dehydrogenase (L-LDH) was cloned from the genomic library of strain MD-1 by complementation in E. coli FMJ144 which was lactate dehydrogenase and pyruvate-formate lyase double defective mutant. The nucleotide sequence of the ldhL gene predicted a protein of 316 amino acid starting with ATG. The putative molecular weight of the L-LDH amino acid sequence was 33.84kD. A putative typical promoter (-35 and -10 boxes) had been observed in the 5' noncoding region. An rho-independent transcriptional terminator has been observed in the 3' noncoding region. Three highly conserved regions (Gly13 approximately Asp50, Asp73 approximately Ileul00 and Asn123 approximately Arg154) with several conserved residues had been identified. Gly13 approximately Asp50 was NADH-binding site domain. Asp73 approximately Ileu100 and Asn123 approximately Arg154 were reported to be the active site domains. The ldhL and the L-LDH of Lactobacillus sp. MD-1 showed the low identity and similarity with other Lactobacilli, and the highest percentage were 61.9% and 68.9% respectively. All the above indicated this gene is a novel ldhL.

Amino Acid Sequence↗
PubMed1998

A thioredoxin fusion protein of VanH, a D-lactate dehydrogenase from Enterococcus faecium: cloning, expression, purification, kinetic analysis, and crystallization.

The gene encoding the vancomycin resistance protein VanH from Enterococcus faecium, a D-lactate dehydrogenase, has been cloned into a thioredoxin expression system (pTRxFus) and expressed as a fusion protein. The use of several other expression systems yielded only inclusion bodies from which no functional protein could be recovered. Experiments to remove the thioredoxin moiety by enterokinase cleavage at the engineered recognition site under a variety of conditions resulted in nonspecific proteolysis and inactivation of the protein. The intact fusion protein was, therefore, used for kinetic studies and crystallization trials. It has been purified to greater than 90% homogeneity by ammonium sulfate precipitation followed by phenyl Sepharose chromatography. Based on k(cat)/KM for pyruvate, it is 20% as active as native VanH. Michaelis constants for NADPH, NADH, and pyruvate, of approximately 3.5 microM, 19.0 microM, and 1.5 mM, respectively, were comparable to those reported for the native VanH (Bugg TDH et al., 1991, Biochemistry 30:10408-10415). Like native VanH, maximum activity of the fusion protein requires the presence of an anion (phosphate or acetate), however, in addition, a strongly reducing environment is needed for optimal efficacy. Competitive inhibition constants for ADP-ribose, NAD+, and oxamate have also been determined. Crystallization by hanging drop vapor diffusion produced two different crystal forms, one hexagonal and the other tetragonal. Flash-frozen crystals of the tetragonal form diffracted to 3.0 A resolution at a synchrotron radiation source.

Amino Acid Sequence↗
PubMed1984

Intramolecular hydride transfer of a combined coenzyme-substrate analog by D- and L-lactate dehydrogenases.

The synthesis of 3-[(3-carboxy-3-oxopropyl)aminocarbonyl]pyridine adenine dinucleotide, a new combined analog of NADH and pyruvate with pyruvate covalently attached to the amide nitrogen atom of the dihydronicotinamide ring via an additional methylene group, is described. In the presence of D-lactate dehydrogenase from Limulus polyphemus, from Lactobacillus leichmannii, and L-lactate dehydrogenase from pig skeletal muscle a redox reaction takes place between the pyruvate moiety and the dihydropyridine ring of the analog. This reaction is shown to be intramolecular by competition experiments with pyruvate. Degradation of the reaction products reveals that the carbon-2 atom of the formed lactate side chain exhibits D configuration in each of these cases studied.

Animals↗
PubMed2002

Catalytic properties of three L-lactate dehydrogenases from saffron corms (Crocus sativus L).

Three L-lactate dehydrogenase isoenzymes were detected in saffron corms, using potassium ferricyanide as the electron acceptor. Their pH optima were 5.5, 7.5 and 9.5, respectively. All three dehydrogenases were substrate-inhibited by ferricyanide, but at different concentrations; maximum enzymatic activity was observed for 250, 100 and 600 microM ferricyanide, at pH 5.5, 7.5 and 9.5, respectively. Catalytic efficiency, calculated per mg corm extract protein, was 1.9, 1.0 and 0.4 min(-1), respectively at pH 5.5, 7.5 and 9.5. Pseudo first order rate constant was also different under the three pH conditions. Malate was an inhibitor for the isoenzyme active at pH 9.5, but had no effect on the others.

Catalysis↗
PubMed1982

Lactate dehydrogenase isoenzymes in human myometrium during pregnancy and labor.

Myometrial lactate dehydrogenase isoenzymes were investigated in 32 pregnant women and in 21 women during labor. During pregnancy and labor the H-type LDH isoenzymes were found to preponderate in contrast to M-type LDH isoenzymes. Both H-LDH and M-LDH isoenzyme activities showed a tendency to increase in normal pregnancy. In severe pre-eclampsia and in chronic hypertension, the uterine M-LDH level decreased. In normal labor, M-LDH activity declined in both the uterine and the rectus abdominis muscles.

Female↗
PubMed1990

Lactate dehydrogenase isoenzymes in squamous cell carcinomas of the oral cavity.

Lactate dehydrogenase (LDH; EC 1.1.1.27) isoenzymes in human epithelial cells from squamous cell carcinomas and healthy tissues of the oral cavity of five patients were analyzed using isoelectric focussing. A new basic isoenzyme and high LDH-7 and LDH-9 activity were found in tumor cells in contrast to epithelial cells of adjoining nontumor tissue. These findings indicate that gradual changes in the percentage distribution of LDH isoenzymes may represent a useful parameter of disease activity in patients with squamous cell carcinomas.

Adult↗
PubMedDate not supplied

[Diagnostic role of organ-specific isoforms of lactate dehydrogenase in blood plasma].

Changes in plasm isoenzymic spectrum of lactate dehydrogenase (LDG), a glycolytic enzyme, were studied in death of cardiovascular diseases, ethanol poisoning and a mechanical injury. The tests used electrophoresis in 1% solution of agarose. Isoenzymic composition differed between the groups with acute coronary failure, chronic coronary heart disease, alcohol cardiomyopathy and a mechanical injury. Ethanol poisoning caused two types of characteristic shifts in LDG isoenzymic spectrum. Nomograms were designed for practical application in forensic medical expertise of sudden death.

Acute Disease↗