Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.37 (malate dehydrogenase)
4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats subjected to physical training through swimming increased their weight at a slower rate than controls, which initially had the same characteristics. The ratio heart weight/body weight was 23% greater in the trained rats. However, the absolute weights of the hearts were only 7% greater. The ultrastructural morphometric study, backed up by and analysis of the hierarchical variance, did not reveal significant changes neither in the myofibrillar and mitochondrial volume nor in the number of mitochondria per surface unit of myocardium. Furthermore, no variations were recorded, due to training, in the amount of mitochondrial protein nor in the specific mitochondrial activities of malate dehydrogenase, cytochrome c oxidase and ATPase. It is therefore suggested that the increase in the measured parameters, due to training, is proportional to the increase in weight and size of the heart. On the other hand, the specific activity of LDH increased by 15% after the first weeks of training.
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PMID:Effects of physical training on rat myocardium. An enzymatic and ultrastructural morphometric study. 59 84

The structure and histochemistry of the palmar and plantar skin were studied in four adult male marmosets (two Callithrix jacchus and two Callithrix penicillata). In this skin there exist well-developed epidermal ridges, to which are attached one or two ducts of sweat glands. A thick stratum corneum can be seen in the epidermis, while a distinct stratum lucidum cannot be isolated from the other layers. The stratum granulosum is constituted by one or three layers of cells containing keratohyalin granules. Melanin granulations are mainly concentrated in the basal cells of the epidermal ridges. Dendritic melanocytes and amelanotic melanocytes containing alkaline phosphatase are found among the epidermal cells. Glycogen, UDPG-GT and phosphorylases are mainly present in the middle and lower Malpighian cells of the epidermal ridges. Alkaline phosphatase, ATPase, alanyl amino-peptidase and leucine aminopeptidase were absent in the epidermal cells. SDH, cytochrome oxidase, MAO and a certain number of NAD-dependent dehydrogenases (LDH, ADH, MDH, alpha-GPDH, beta-OHBDH and GDH) showed a stronger reactivity in the basal cells and Malpighian layer. The NADP-dependent enzymes (G-6-PDH, 6-PGDH, cis-aconistase and ICDH) were more reactive in the upper Malpighian layer and stratum granulosum. The stratum corneum showed some acid phosphatase and nonspecific esterase reactivity. The collagenous fibers intertwined with a small number of very thin elastic ones and a larger amount of reticular fibers run almost parallel to the epidermal ridges in the papillary body. In the reticular dermis some fibers are disposed transversely to the epidermal ridges. Meissner corpuscles reactive to butyrylcholinesterase, acetylcholinesterase, nonspecific esterase and G-6-PA are disposed at regular intervals and frequently at each side of the epidermal ridges. Pacinian corpuscles were found only in the hypodermis. The eccrine sweat glands contain glycogen, UDPG-GT and phosphorylase in their secretory, ductal and myoepithelial cells. The secretory part shows a uniform reactivity for every dehydrogenase because it contains only one type of cells (clear cells). The intraepidermal segment of the ducts shows a stronger reactivity to nonspecific esterase and NADP-dependent dehydrogenases than the epithelial cells around it.
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PMID:The skin of the palms and soles of the marmosets (Callithrix jacchus and Callithrix penicillata). 82 86

Histologic investigations together with histochemical and photometric measurements of enzyme activities were performed in retina of rabbits, whose blood supply had been totally interrupted for 1h. A retinal edema developed affecting the internal layers between the inner limiting membrane and the internal plexiform and ganglion cell layer. Although this edema was quite remarkable at the posterior pole of the eye, it diminished toward the periphery, disappearing near the ora serrata. The activities of the following enzymes were investigated: hexokinase, glucose 6-phosphate dehydrogenase, aldolase, glyceraldehydephosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, ATPase, and phosphorylase. The most striking finding was the total disappearance of phosphorylase activity under pressure ischemia. ATPase and aldolase showed a decreased activity in the ischemic retina, and malate dehydrogenase a slightly diminished one. Concerning the other enzymes, no significant differences between normal and ischemic retina were observed.
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PMID:Enzymologic and histologic investigations in normal and pressure-ischemic retina of rabbits. 108 79

Palmitylcarnitine oxidation by isolated liver mitochondria has been used to investigate the interaction of fatty acid oxidation with malate, glutamate, succinate, and the malate-aspartate shuttle. Mitochondria preincubated with fluorocitrate were added to a medium containing 2mM ATP and ATPase. This system, characterized by a high energy change, allowed titration of respiration to any desired rate between States 4 and 3 (Chance, B., and Williams, G. R. (1956) Adv. Enzymol. Relat. Areas Mol. Biol. 17, 65-134). When respiration (reference, with palmitylcarnitine and malate as substrates) was set at 75% of State 3, the oxidation of palmitylcarnitine was limited by acetoacetate formation. The addition of malate or glutamate approximately doubled the rate of beta oxidation. Malate circumvented this limitation by citrate formation, but the effect of glutamate apparently was due to enhancement of the capacity for ketogenesis. The rate of beta oxidation was curtailed when malate and glutamate were both present. This curtailment was more pronounced when the malate-aspartate shuttle was fully reconstituted. Among the oxidizable substrates examined, succinate was most effective in inhibiting palmitylcarnitine oxidation. Mitochondrial NADH/NAD+ ratios were correlated positively with suppression of beta oxidation. The degree of suppression of beta oxidation by the malate-aspartate shuttle (NADH oxidation) or by succinate oxidation was dependent on the respiratory state. Both substrates extensively reduced mitochondrial NAD+ and markedly suppressed beta oxidation as respiration approached State 4. Calculations of the rates of flux of hydrogen equivalents through beta oxidation show that the suppression of beta oxidation by glutamate or by the malate-aspartate shuttle is accounted for by increased flux of reducing equivalents through mitochondrial malic dehydrogenase. This increased Flux is accompanied by an increase in the steady state NADH/NAD+ ratio and a marked decrease in the synthesis of citrate. The alpha-glycerophosphate shuttle was reconstituted with mitochondria isolated from rats treated with L-thyroxine. This shuttle was about equal to the reconstructed malate-aspartate shuttle in supression of palmitylcarnitine oxidation. This interaction could not be demonstrated in euthyroid animals owing to the low activity of the mitochondrial alpha-glycerol phosphate dehydrogenase. It is concluded that beta oxidation can be regulated by the NADH/NAD+ ratio. The observed stimulation of flux through malate dehydrogenase both by glutamate and by the malate-aspartate shuttle results in an increased steady state NADH/NAD+ ratio, and is linked to a stoichiometric outward transport of aspartate. We suggest, therefore, that some of the reducing pressure exerted by the malate-aspartate shuttle and by glutamate plus malate is provided through the energy-linked, electrogenic transport of aspartate out of the mitochondria. These results are discussed with respect to the mechanism of the genesis of ethanol-induced fatty liver.
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PMID:Suppression of the mitochondrial oxidation of (-)-palmitylcarnitine by the malate-aspartate and alpha-glycerophosphate shuttles. 124 72

The influence of lysophosphatidylcholine (LPC) on H(+)-ATPase, cytochrome oxidase (COX), glycerolphosphate dehydrogenase (GPDH) and malate dehydrogenase (MDH) was followed. The activities of H(+)-ATPase and COX increased with increasing LPC concentration up to 0.5 mg/mg protein when maxima were achieved. This activatory effect is LPC-specific, because Lubrol-treated or frozen-thawed mitochondria showed lower activities of these enzymes. H(+)-ATPase was not influenced by higher concentration of LPC, while COX activity decreased with increasing amount of LPC. The activity of GPDH decreased at very low concentration of LPC and was not further modified at higher LPC concentration. In an attempt to find the concentration of LPC necessary for a complete permeabilization of inner mitochondrial membrane we followed the influence of lysolipid on the release of MDH activity from the mitochondrial matrix. The full activity of this enzyme was obtained with a concentration 0.75 mg LPC/mg protein indicating that mitochondria were completely broken. Our data indicate that LPC significantly affects activity of enzymes connected with mitochondrial membrane and can be useful for evaluation of the importance of phospholipid microenvironment for the enzyme function.
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PMID:The effect of lysophosphatidylcholine on the activity of various mitochondrial enzymes. 130 53

Ubiquinol-1 in aerated aqueous solution inactivates several enzymes--alanine aminotransferase, alkaline phosphatase, Na+/K(+)-ATPase, creatine kinase and glutamine synthetase--but not isocitrate dehydrogenase and malate dehydrogenase. Ubiquinone-1 and/or H2O2 do not affect the activity of alkaline phosphatase and glutamine synthetase chosen as model enzymes. Dioxygen and transition metal ions, even if in trace amounts, are essential for the enzyme inactivation, which indeed does not occur under argon atmosphere or in the presence of metal chelators. Supplementation with redox-active metal ions (Fe3+ or Cu2+), moreover, potentiates alkaline phosphatase inactivation. Since catalase and peroxidase protect while superoxide dismutase does not, hydrogen peroxide rather than superoxide anion seems to be involved in the inactivation mechanism through which oxygen active species (hydroxyl radical or any other equivalent species) are produced via a modified Haber-Weiss cycle, triggered by metal-catalyzed oxidation of ubiquinol-1. The lack of efficiency of radical scavengers and the almost complete protection afforded by enzyme substrates and metal cofactors indicate a 'site-specific' radical attack as responsible for the oxidative damage.
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PMID:Enzyme inactivation by metal-catalyzed oxidation of coenzyme Q1. 135 46

We have shown previously that cleavage of a number of precursors by the mitochondrial processing peptidase (MPP) requires an intermediate octapeptide (FXXSXXXX) between the MPP cleavage site and the mature protein amino terminus. We show now that these octapeptides, present at the amino termini of the intermediates, direct recognition of these substrates by the mitochondrial intermediate peptidase (MIP), leading to formation of mature proteins. Synthetic peptides, corresponding to the intermediate octapeptides of human ornithine transcarbamylase (OTC) and of Neurospora cytochrome c reductase Fe/S subunit (Fe/S), inhibit the processing activity of purified rat liver MIP in vitro, without affecting MPP activity; this indicates that the octapeptides can be recognized by MIP independent of the presence of the corresponding mature proteins and interact with a site that is crucial for MIP activity. MIP activity is not inhibited by a peptide lacking the amino-terminal hydrophobic residue, while substitution of such a residue by a polar amino acid causes a 10-fold reduction in the efficiency of MIP inhibition. To analyze the requirements for removal of the octapeptide from the intermediate proteins by MIP, artificial intermediates were synthesized and subjected to in vitro processing by purified MIP. The octapeptide can be cleaved by MIP only when the amino-terminal hydrophobic residue is also the amino terminus of the intermediate. Further, when the OTC octapeptide is joined to the mature amino terminus of another twice-cleaved precursor (pFe/S; rat malate dehydrogenase, pMDH), the chimeric intermediate is cleaved by MIP to the corresponding mature-sized protein. When the OTC octapeptide is joined to the mature amino terminus of a once-cleaved precursor (yeast F1-beta-ATPase, pF1-beta), however, this intermediate is not cleaved by MIP; rather, it is processed by MPP to mature-sized F1-beta. Therefore, amino-terminal octapeptides can be cleaved by MIP only within the structural context of twice-cleaved precursors.
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PMID:Amino-terminal octapeptides function as recognition signals for the mitochondrial intermediate peptidase. 156 19

Some histochemical changes in adult C. sinensis collected from rats infected artificially and treated with pyquiton were observed. 1 h after administration the glycogen content showed a slight decrease which became prominent 24h later and almost disappeared at 48h post-medication. There was an increase in protein content in the parenchymal tissues of worms 1h after treatment, especially in the reproductive organ 24h after treatment. RNA content was decreased 1h post administration and continued decreasing gradually so that very little could be seen 48h later. An increase in the activities of SDH, MDH and Ca-ATPase was seen at the beginning and became marked 24h after medication, while that for G-6-PDH was detected 48h after drug administration. No obvious changes in DNA, lipid, AKP, ACP and phenolase were detected within 1-48h after treatment.
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PMID:[Histochemical changes in Clonorchis sinensis after pyquiton treatment]. 169 37

The effects of arachidonic acid on the enzyme complexes in the electron transport system were investigated using submitochondrial particles from rat brain. Arachidonic acid irreversibly inhibited NADH-CoQ oxidoreductase (complex I) activity, but had no effect on the activities of succinate-CoQ oxidoreductase (complex II), CoQH2-cytochrome c oxidoreductase (complex III), cytochrome c oxidase (complex IV), ATPase (complex V), glutamate dehydrogenase, and malate dehydrogenase up to 50 microM. The inhibition was dose-dependent with an IC50 value of 110 nmol/mg protein. The Lineweaver-Burk plot revealed that the inhibition by arachidonic acid was noncompetitive against CoQ with a Ki value of 33 microM and uncompetitive against NADH with a Ki value of 22 microM.
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PMID:Selective inhibition of NADH-CoQ oxidoreductase (complex I) of rat brain mitochondria by arachidonic acid. 190 30

Administration of different doses of L-thyroxine (T4) and triiodo-L-thyronine (T3) in vivo in G. carnosus stimulated the activities of cytochrome oxidase, alpha-glycerophosphate dehydrogenase (alpha-GPDH), succinate dehydrogenase (SDH), and Mg2+ adenosine triphosphatase (Mg2+ ATPase) and inhibited the activity of malate dehydrogenase (MDH). While a low dose of thiouracil administration produced a stimulatory effect on cytochrome oxidase and alpha-GPDH activities, a higher dose of thiouracil significantly inhibited the activities of cytochrome oxidase, alpha-GPDH, SDH, Mg2+ ATPase, and MDH. Injection of T4 or T3 into thiouracil-treated animals significantly restored the stimulatory effect of thyroid hormones on oxidative enzyme activities. It is suggested that thyroid hormones in vivo increase and that thiouracil decreases the oxidative capacity of hepatic mitochondria of G. carnosus.
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PMID:Stimulation of oxidative metabolism by thyroid hormones in an apodan amphibian, Gegenophis carnosus (Beddome). 216 65


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