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At least 973 records · Page 54Linked to original sources
PubMed1992

Purification and determination of the binding site of lactate dehydrogenase from chicken breast muscle on immobilized ferric ions.

Lactate dehydrogenase from chicken breast muscle was purified to homogeneity in one step by immobilized metal ion affinity chromatography. The purified enzyme was used to localize the binding site to immobilized Fe(III) ions. After cyanogen bromide degradation and digestion with trypsin, small enzyme fragments capable of binding to immobilized Fe(III) ions were obtained. It is proposed that several histidyl groups are involved in the binding.

Amino Acid Sequence↗
PubMed1976

The use of NADH as a standard in a modified PMS-INT colorimetric assay of lactate dehydrogenase.

A new and more reliable way of quantitating lactate dehydrogenase activity, using NADH as a standard in a colorimetric assay, is proposed. Adopting the scheme, we obtained a CV of 2.6% and precision (95% limits) of +/-5.4% for enzyme activities ranging from 110 to 600 U/l. Comparative study against the modified kinetic method of Amador et al. showed excellent correlation, r = 0.99, p less than 0.001. A normal range of 75 to 203 U/l was determined for the proposed scheme.

Colorimetry↗
PubMed1993

Kinetic analysis of lactate dehydrogenase using integrated rate equations.

The reaction catalyzed by lactate dehydrogenase was analyzed under fully second-order conditions using integrated rate equations. A two-step regression analysis was utilized to fit twenty-one progress curves repeated in sextuplicate to the general mechanism second-order integrated rate equation with additional terms of substrate inhibition. The fitting error was less than one percent. The resulting kinetic constants support a ternary complex mechanism; in no case were constants supporting another mechanism predicted. The inhibition constant for oxamate was also determined.

Animals↗
PubMed1976

[In vivo and in vitro effect of hyperbaric oxygen on lactate dehydrogenase activity of serum and organs of the mouse].

Lactate dehydrogenase activity in Mouse liver, kidney and lung was decreased after exposure to hyperbaric oxygen (1,8 atm) in vivo and in vitro. Oxygen inhibitory effect could occur through the oxidation of LDH essential free sulfhydryl groups. Serum LDH activity was diminished in vitro, while it was strongly increased in vivo. This enhancement probably resulted from the release in serum of cellular enzymes proceeding from oxygen injured tissues. Oxygen might inhibit both H and M LDH sub-units, since isozyme pattern was different in each organ.

Animals↗
PubMed1972

Purification and properties of L(+)-lactate dehydrogenase from potato tubers.

1. A purification of l(+)-lactate dehydrogenase is described. 2. The final preparation is active with NADH and NADPH and with a number of keto acids, but evidence is presented to support the view that a single enzyme is involved. 3. NAD(+) showed product inhibition, but at slightly acid pH values there was evidence of co-operative binding. 4. At acid pH values ATP was a potent inhibitor and appears to be an allosteric effector. At neutral or alkaline pH values ATP behaved as a weak competitive inhibitor. 5. The physiological significance of inhibition by ATP is discussed.

Adenosine Triphosphate↗
PubMed1978

Lactate dehydrogenase isoenzyme pattern: marker for differentiation of lymphocytes.

The lactate dehydrogenase isoenzyme pattern has been determined in different murine thymocyte cell populations. Enrichment of thymocytes with more mature cells through total irradiation results in a smaller percentage of LDH-1, LDH-2, LDH-3 and a greater percentage of LDH-4 and LDH-5. Fractionation of normal thymocytes by velocity sedimentation at unit gravity yields a fraction of cells with a high sedimentation rate. LDH-1 and LDH-2 formed a smaller percentage of the total enzyme activity in these cells. These findings indicate that the LDH isoenzyme distribution is a marker for differentiation of thymocytes.

Animals↗
PubMed1982

Falsely negative laboratory diagnosis for myocardial infarction owing to the concurrent presence of macro creatine kinase and macro lactate dehydrogenase.

Macro creatine kinase (CK, EC 2.7.3.2) and macro lactate dehydrogenase (LD, EC 1.1.1.27) were both present in the serum of a 70-year-old woman with myocardial infarction. This interfered with the interpretation of the CK and LD isoenzyme analyses. Gel filtration and immunoprecipitation showed that the macro CK consisted of IgG and CK and the macro LD of IgG and LD. The IgG in this patient bound both MB and BB isoenzymes of CK, resulting in a macro CK complex that co-migrated with CK-MM on cellulose acetate electrophoresis. This situation led to a falsely negative laboratory diagnosis for myocardial infarction.

Aged↗
PubMed1986

Lactate dehydrogenase inhibition by immunoglobulin G in human serum.

Low lactate dehydrogenase (LD; EC 1.1.1.27) activity and an abnormal LD pattern in electrophoretograms of LD isoenzymes in the sera of two patients were caused by inhibition of LD by immunoglobulin G. One of these showed inhibitor activity in the serum upon direct analysis, while the other showed activity only after the immunoglobulin was stripped from the LD. As judged from the LD isoenzyme patterns in serum, the LD inhibitor appeared to act against M subunits. However, quantification of binding affinities to each isolated isoenzyme showed that the LD inhibitor had a stronger effect on LD isoenzymes 2 and 3 (H3M1 and H2M2, respectively).

Aged↗
PubMed1988

High resolution of human lactate dehydrogenase: new multiple forms and potential tumor markers.

Human lactate dehydrogenase (LDH) was investigated by ultrathin-layer polyacrylamide gel isoelectric focusing (IEF). In serum, approximately 15 bands and in lyzates of erythrocytes approximately 20 bands were detected. Known LDH isoenzymes (identified by markers) appeared in the zymograms as follows: LDH-1 as a single or double band, LDH-2 as a single band in serum and in the marker, and as a double band in hemolyzate, LDH-3 as a double band, and LDH-4 and LDH-5 each as a single band. LDH-1 was partly inactivated, probably due to deamidation in the acidic range of the pH gradient. Potential LDH tumor markers were detected in different tumor cytosols.

Biomarkers, Tumor↗
PubMed1998

Transgenic mice demonstrate a testis-specific promoter for lactate dehydrogenase, LDHC.

The mammalian genome encodes a family of lactate dehydrogenase (LDH) isozymes. Two of these, ldha and ldhb, are expressed ubiquitously. The ldhc gene is active only in the germinal epithelium during spermatogenesis. In our analysis of ldhc gene regulation, we found that a 60-base pair promoter sequence was sufficient for testis-specific expression in an in vitro transcription assay. To confirm these findings, a genomic fragment containing 100 base pairs overlapping the transcription start site was isolated and linked to the Escherichia coli lacZ gene. We report that this genomic fragment drives testis-specific expression in transgenic mice. We conclude that transcription of the transgene and possibly of the endogenous ldhc gene is restricted to leptotene/pachytene primary spermatocytes.

Animals↗
PubMedDate not supplied

Lactate dehydrogenase (LDH) isoenzymes patterns in ocular tumours.

Estimation of lactate dehydrogenase (LDH) isoenzymes in the serum and aqueous humor was carried out in 15 cases of benign ocular tumour, 15 cases of malignant tumor and 15 normal cases. Cases of both sexes aged between 1 year and 75 years were included. LDH, isoenzymes specially LDH4 and LDH5 are higher and LDH1 and LDH2 lower in sera of patients with malignant tumor specially retinoblastoma as compared to benign tumor cases and control cases. LDH isoenzymes in aqueous humor are significantly higher and show a characteristic pattern in retinoblastoma cases, the concentration was presumably too low in the control, malignant tumor other than retinoblastoma and benign tumor cases as its fractionation was not possible.

Adolescent↗
PubMed1966

Isoenzymes of lactate dehydrogenase in human gastric mucosa and gastric carcinoma tissue.

Lactate dehydrogenase (LDH) isoenzymes were demonstrated electrophoretically in human fundic and pyloric gastric mucosae and in gastric carcinoma tissue. Fundic gastric mucosa consistently displayed a pattern with predominance of LD1, LD2, and LD3. Pyloric gastric mucosa and cancer tissue consistently had identical patterns with a predominance of LD2, LD3, and LD4, differing significantly from the LDH isoenzyme pattern of fundic mucosa. The LDH isoenzyme pattern characteristic of fundic mucosa extended very close to the histological junction between body and pyloric gastric mucosa and was not affected by the presence of gastritis in the stomach. These results serve to demonstrate yet another difference between mucosa from the acid-secreting and the pyloric areas of the human stomach.

Gastric Mucosa↗
PubMed1986

Cerebrospinal fluid lactate dehydrogenase activities in patients with central nervous system metastases.

Lactate dehydrogenase activities were determined in CSF from 350 patients suffering from various neurological diseases. Reference values were established as 0-26 U/l. Slight elevations of CSF LDH activities were observed in patients with the following disorders: brain metastasis and spinal epidural metastasis from solid carcinomas, primary central nervous system tumours, cerebrovascular accident, polyneuropathy and head injury. Marked elevations were observed incidentally in patients in these groups and in a considerable number of patients with bacterial meningitis and with leptomeningeal spread from solid or haematologic malignancies. When other diagnostic information is available for the proper estimation of the pre-test likelihood of disease, CSF LDH activities exceeding 50 U/l are suggestive for meningeal carcinomatosis.

Adolescent↗
PubMed1992

Evolutionary implications of the cDNA sequence of the single lactate dehydrogenase of a lamprey.

All vertebrates other than lampreys exhibit multiple loci encoding lactate dehydrogenase +ADL-LDH; (S)-lactate:NAD+ oxidoreductase, EC 1.1.1.27+BD. Of these loci, Ldh-A is expressed predominantly in muscle, Ldh-B is expressed predominantly in heart, and Ldh-C (where present) exhibits different tissue-restricted patterns of expression depending on the taxon. To examine the relationship of the single LDH of lampreys to other vertebrate LDHs, we have determined the cDNA sequence of the LDH of the sea lamprey Petromyzon marinus and compared it to previously published sequences from bacteria, plants, and vertebrates. The lamprey sequence exhibits a mixture of features of both LDH-A and LDH-B at the amino acid level that may account for its intermediate kinetic properties. Both distance and maximum parsimony analyses strongly reject a relationship of lamprey LDH with mammalian LDH-C but do not significantly distinguish among remaining alternative phylogenetic hypotheses. Evolutionary parsimony analyses suggest that the lamprey LDH is related to Ldh-A and that the single locus condition has arisen as a result of the loss of Ldh-B (prior to the appearance of Ldh-C). The collection of LDH sequences for further studies of the evolution of the vertebrate LDH gene family will be facilitated by the PCR approach that we have used to obtain the lamprey sequence.

Amino Acid Sequence↗
PubMed1969

Linkage of lactate dehydrogenase B and C loci in pigeons.

Synthesis of lactate dehydrogenase in somatic and gametic tissues of certain avian and mammalian species is controlled by alleles at three loci, A, B, and C. We report breeding experiments with pigeons that conclusively demonstrate linkage between the B and C structural loci in this species. The most probable recombination fraction is zero, and contiguity is not excluded. The upper 95 percent probability limit is 4.5 percent. This tight linkage of two loci that produce closely similar polypeptides suggests that the loci acquired their separate identities through a duplication event. Further-more, the existence of recognizable B- and C-type polypeptides in both the bird and the mammal suggests that the event and the resulting linkage preceded the separation of these fauna. If so, then the linkage has persisted for a very long time.

Alleles↗
PubMed1989

Cyclic changes in salivary lactate dehydrogenase, peroxidase and leucine aminopeptidase during menstrual cycle.

Salivary lactate dehydrogenase (LDH), peroxidase (Px) and leucine aminopeptidase (LAP) activities were scanned in both normally ovulating and anovulating women during entire menstrual cycle. In ovulating women, all the three enzymes exhibited significant increase in the activity on or before the onset of ovulation which was monitored by the shift of the basal body temperature (BBT) as well as the ferning pattern of the cervical mucus. The peak maximum at the midcycle was several times higher than the previous day value in all the six normal women. In anovulatory women, no such remarkable change in the enzyme activities was found throughout the cycle. Salivary LDH and LAP showed peak at the midcycle and at the same time required short time for assay, so the present results are strongly suggestive that the determination of salivary enzyme content may be a convenient method for detecting the day of ovulation.

Female↗
PubMed1978

[Genetic regulation of the lactate dehydrogenase isoenzyme spectrum in mouse erythrocytes].

The pattern of lactate dehydrogenase isozymes was investigated by means of electrophoresis in erythrocytes of CBA/Lac and DBA/2J mice homozygous for b and a alleles of the Ldr-1 locus. It is found that differences in the pattern of LDH isozymes, homozygous for the genes Ldr-1a and Ldr-1b, consist in increased activity of the isozyme LDH-4 in mice homozygous for the gene Ldr-1a (DBA/2J) within 12-14 days of postnatal development. Inhibition of the reaction between 125I-LDH-1 and the respective antibodies has demonstrated that increased LDH-4 activity during development is related to the higher content of B-subunits of LDH. It is suggested that the mechanism of the action of the gene Ldr-1 involves changes in the rate of the synthesis and degradation of B-subunit of LDH.

Alleles↗
PubMed1980

[Analysis of lactate dehydrogenase isoenzymes in murine lymphocyte populations].

The pattern of lactate dehydrogenase isoenzyme has been examined for different murine lymphoid cell populations and for T and B lymphocyte populations. LDH-1, LDH-2, LDH-3, LDH-4 and LDH-5 were found in the thymus, LDH-3, LDH-4 and LDH-5 in the spleen, and LDH-4 and LDH-5 in lymph nodes. Enrichment of lymphocytes with T and B cells resulted in the appearance of LDH-4 and LDH-5 in T cell population, and of LDH-5 in B cell population. With the appearance of the autoimmune reaction, activity of LDH-5 in the thymus was seen to decrease. After the thymosin injection (4 fraction), activities of LDH-1, LDH-2 and LDH-3 diminished. A possible application of the LDH isoenzyme distribution pattern as a marker of T cell differentiation is discussed.

Animals↗