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Enzyme
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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)
Enzymatic activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (EC 4.1.1.39), phospho(enol)pyruvate carboxylase (EC 4.1.1.31), NAD
malate dehydrogenase
(
EC 1.1.1.37
), and NADP glyceraldehydephosphate dehydrogenase complex including phosphoglycerate kinase (EC 2.7.2.3) and glyceraldehydephosphate dehydrogenase (EC 1.2.1.13) were comparatively assayed in wheat seedlings of the cultivar Lyutestsens 758 grown under normal conditions,
water
deficiency conditions, and subsequent rehydration.
Water
stress was found to decrease the activity of all enzymes tested, the effect being most pronounced in case of Rubisco. The content of Rubisco in wheat plants exposed to
water
deficiency was reduced less significantly than the activity of the enzyme. Preliminary treatment of plant seeds with kartolin-4 (o-isopropyl-N-2-hydroxyethyl carbamate), a preparation with cytokinin activity, reduced the dehydration-induced inhibition of enzymatic activity. Upon a subsequent rehydration, kartolin-4 facilitated rapid recovery of the photosynthetic activity, the process being based on the kartolin-induced stimulation of reparation reactions. Under conditions of
water
stress, a partial decrease in the activity of carbon metabolism enzymes in vitro was accompanied by complete inhibition of photosynthesis in vivo, perhaps, as a result of an abrupt increase in the stomatal resistance.
...
PMID:[Activity of carbon metabolism enzymes in wheat plants treated with kartolin-4 and exposed to water stress]. 1177 26
A vacuum infiltration technique was developed that enabled the extraction of apoplastic solution with very little cytoplasmic contamination as evident from a
malate dehydrogenase
activity of less than 1% in the apoplastic solution relative to that in bulk leaf extracts. The volume of apoplastic
water
, a prerequisite for determination of the concentration of apoplastic solutes, was determined by vacuum infiltration of indigo carmine with subsequent analysis of the dilution of the dye in apoplastic extracts. Indigo carmine was neither transported across the cell membrane nor significantly adsorbed to the cell walls, ensuring reproducible (SE < 2%) and precise determination of apoplastic
water
. Analysis of leaves from four different positions on senescing Brassica napus plants showed a similar apoplastic pH of 5.8, while apoplastic NH4+ increased from 1.1 mM in lower leaves to 1.3 mM in upper leaves. Inhibition of glutamine synthetase in young B. napus plants resulted in increasing apoplastic pH from 6.0 to 6.8 and increasing apoplastic NH4+ concentration from 1.0 to 25.6 mM, followed by a marked increase in NH3 emission. Calculating NH3 compensation points for B. napus plants on the basis of measured apoplastic H+ and NH4+ concentrations gave values ranging from 4.3 to 5.9 nmol NH3 mol-1 air, consistent with an estimate of 5.3 [plus or minus] 3.6 nmol NH3 mol-1 air obtained by NH3 exchange experiments in growth chambers. A strong linear relationship was found between calculated NH3 compensation points and measured NH3 emission rates in glutamine synthetase-inhibited plants.
...
PMID:Apoplastic pH and Ammonium Concentration in Leaves of Brassica napus L. 1222 82
The three-dimensional crystal structure of the (R207S, R292S) mutant of
malate dehydrogenase
from Haloarcula marismortui was solved at 1.95A resolution in order to determine the role of salt bridges and solvent ions in halophilic adaptation and quaternary structure stability. The mutations, located at the dimer-dimer interface, disrupt two inter-dimeric salt bridge clusters that are essential for wild-type tetramer stabilisation. Previous experiments in solution, performed on the double mutant, had shown a tetrameric structure in 4M NaCl, which dissociated into active dimers in 2M NaCl. In order to establish if the active dimeric form is a product of the mutation, or if it also exists in the wild-type protein, complementary studies were performed on the wild-type enzyme by analytical centrifugation and small angle neutron scattering experiments. They showed the existence of active dimers in NaF, KF, Na(2)SO(4), even in the absence of NADH, and in the presence of NADH at concentrations of NaCl below 0.3M. The crystal structure shows a tetramer that, in the absence of the salt bridge clusters, appears to be stabilized by a network of ordered
water
molecules and by Cl(-) binding at the dimer-dimer interface. The double mutant and wild-type dimer folds are essentially identical (the r.m.s. deviation between equivalent C(alpha) positions is 0.39A). Chloride ions are also observed at the monomer-monomer interfaces of the mutant, contributing to the stability of each dimer against low salt dissociation. Our results support the hypothesis that extensive binding of
water
and salt is an important feature of adaptation to a halophilic environment.
...
PMID:The Oligomeric states of Haloarcula marismortui malate dehydrogenase are modulated by solvent components as shown by crystallographic and biochemical studies. 1258 46
The induction of CAM in Pedilanthus tithymaloides (Euphorbiaceae) under
water
-limited conditions was evaluated by following diurnal oscillations of CO2 fixation, titratable acidity and malic acid content in the leaf extracts. CAM induction was assessed by measuring the activities of phosphoenolpyruvate carboxylase (PEPC), NADH-
malate dehydrogenase
(
MDH
) and phosphoenolpyruvate caroxykinase (PEPCK) in the leaves as well. Drought resulted in large increases in the nocturnal acid accumulation and rates of CO2 uptake in the leaves of P. tithymaloides. The drought-induced CAM activity tended to be reversible after re-watering. Nevertheless, under well-watered conditions, plants of P. tithymaloides showed day time CO2 uptake patterns with less pronounced diurnal oscillations of organic acids. Our data indicate that although P. tithymaloides is a CAM plant, environmental variables like drought induce photosynthetic flexibility in this species. This type of plasticity in CAM and metabolic versatility in P. tithymaloides should be an adaptation for prolonged survival under natural adverse edaphic and microclimate situations.
...
PMID:Photosynthetic flexibility in Pedilanthus tithymaloides poit, a CAM plant. 1268 49
The
malic dehydrogenase
activity was determined by the modified method of Ochoa (1955) using tissue homogenates of various parasitic helminths. Worm parasites were mostly collected from local abattoir, and removed from the organ or tissues of the naturally infected animal hosts, and some materials were also obtained from the human hosts. The helminths used in this experiment include 3 kinds of nematodes, 5 kinds of trematodes, and 8 kinds of cestodes. They were throughly washed and homogenized in glass tissue grinder in ice chilled
water
bath, and then centrifuged. The supernatants were designated as enzyme preparations. The hydrogen concentrations of buffer solution were pH 1.4, 2.7, 3.5, 4.2, 5.2, 7.4, 8.2, 9.3, 10.2, 11.6, and enzymatic reaction of this experiment was performed at incubation temperature of 20, 30, 40, and 50 degrees C. The extinction of Nicotinamide Adenosine Dinucleotide (NAD) was measured by spectrophotometry at the wave length of 340 millimicron. The results of the experiment were as follows: 1. The
malic dehydrogenase
activity occurred over all kinds of parasitic helminths used in this study. And the activity on sparganum turned out to be highest. 2. All helminths displayed their maximum activity in the range of alkaline pH. 3. A comparison of the effects of temperature and substrate concentration on the enzyme activity was made among these helminths. However, no definite relationship among them has been detected. 4. The significance of the existence of this enzyme in the helminths was briefly discussed.
...
PMID:[Studies On Malic Dehydrogenase Activity In Parasitic Helminths] 1291 53
Sea urchin embryos grown in salt
water
containing L-malate showed a pattern of development of
L-malate dehydrogenase
which did not differ from that of embryos grown in s lt
water
. However, embryos grown in 10-(3)M D-malate for 6 or 12 hours had one additional band of
L-malate dehydrogenase
that was not present in control embryos of the same age.
...
PMID:D-MALATE: EFFECTS ON ACTIVITY OF L-MALATE DEHYDROGENASE IN DEVELOPING SEA URCHIN EMBRYOS. 1420 70
A genetic approach was cited for species detection of the ameba genus Naegleria using allozyme electrophoresis to characterize the trophozoite stage of three strains of Naegleria fowleri isolated from patients with primary amebic meningoencephalitis, five thermophilic (45 degrees C) Naegleria spp isolated from natural
water
sources in the Taling Chan district, and a reference control strain, Naegleria fowleri CDC VO 3081. Isoenzymes of ameba whole-cell extracts were analyzed by vertical polyacrylamide slab gel electrophoresis to determine whether there was any correlation between different strains of the ameba. The results showed that five out of fifteen enzymes; aldehyde oxidase (ALDOX), aldolase (ALD), a-glycerophosphate dehydrogenase (a-GPDH), xanthine dehydrogenase (XDH), and glutamate oxaloacetate transaminase (GOT), were undetectable in the pathogenic strains, while the other enzymes; esterase (EST), fumerase (FUM), glucose-6-phosphate dehydrogenase (G-6-PDH), glucose phosphate isomerase (GPI), isocitate dehydrogenase (IDH), lactate dehydrogenase (LDH), leucine aminopeptidase (LAP), malic enzyme (ME), glucose phosphomutase (GPM), and
malate dehydrogenase
(
MDH
), were detected. Naegleria fowleri strains were biochemically the most homogeneous. They showed intraspecific isoenzyme variation that allowed them to be grouped. In contrast, the allozyme patterns (EST 1-7, IDH) of Naegleria spp isolated from the environment showed interspecific isoenzyme variations from the pathogenic Naegleria strain. In conclusion, this study recognized the zymograms of the Naegleria fowleri strains were heterogenically different from the thermophilic 45 degrees C Naegleria spp isolated from the environment.
...
PMID:Zymogram patterns of Naegleria spp isolated from natural water sources in Taling Chan district, Bangkok. 1569 Nov 24
Several complementary studies were undertaken on a single species of deep-sea fish (the eel Synaphobranchus kaupii) within a small temporal and spatial range. In situ experiments on swimming and foraging behaviour, muscle performance, and metabolic rate were performed in the Porcupine Seabight, northeast Atlantic, alongside measurements of temperature and current regime. Deep-
water
trawling was used to collect eels for studies of animal distribution and for anatomical and biochemical analyses, including white muscle citrate synthase (CS), lactate dehydrogenase (LDH),
malate dehydrogenase
(
MDH
), and pyruvate kinase (PK) activities. Synaphobranchus kaupii demonstrated whole-animal swimming speeds similar to those of other active deep-sea fish such as Antimora rostrata. Metabolic rates were an order of magnitude higher (31.6 mL kg(-1) h(-1)) than those recorded in other deep-sea scavenging fish. Activities of CS, LDH,
MDH
, and PK were higher than expected, and all scaled negatively with body mass, indicating a general decrease in muscle energy supply with fish growth. Despite this apparent constraint, observed in situ burst or routine swimming performances scaled in a similar fashion to other studied species. The higher-than-expected metabolic rates and activity levels, and the unusual scaling relationships of both aerobic and anaerobic metabolism enzymes in white muscle, probably reflect the changes in habitat and feeding ecology experienced during ontogeny in this bathyal species.
...
PMID:High swimming and metabolic activity in the deep-sea eel Synaphobranchus kaupii revealed by integrated in situ and in vitro measurements. 1588 80
Epithelial cells of the thick ascending limb of Henle's loop (TALH cells) play a major role in the urinary concentrating mechanism. They are normally exposed to variable and often very high osmotic stress, which is particularly due to high sodium and chloride reabsorption and very low
water
permeability of the luminal membrane. It is already established that elevation of the activity of aldose reductase and hence an increase in intracellular sorbitol are indispensable for the osmotic adaptation and stability of the TALH cells. To identify new molecular factors potentially associated with the osmotic stress-resistant phenotype in kidney cells, TALH cells exhibiting low or high levels of resistance to osmotic stress were characterized using proteomic tools. Two-dimensional gel analysis showed a total number of 40 proteins that were differentially expressed in TALH cells under osmotic stress. Twenty-five proteins were overexpressed, whereas 15 proteins showed a down-regulation. Besides the sorbitol pathway enzyme aldose reductase, whose expression was 15 times increased, many other metabolic enzymes like glutathione S-transferase,
malate dehydrogenase
, lactate dehydrogenase, alpha enolase, glyceraldehyde-3-phosphate dehydrogenase, and triose-phosphate isomerase were up-regulated. Among the cytoskeleton proteins and cytoskeleton-associated proteins vimentin, cytokeratin, tropomyosin 4, and annexins I, II, and V were up-regulated, whereas tubulin and tropomyosins 1, 2, and 3 were down-regulated. The heat shock proteins alpha-crystallin chain B, HSP70, and HSP90 were found to be overexpressed. In contrast to the results in oxidative stress the endoplasmic reticulum stress proteins like glucose-regulated proteins (GRP78, GRP94, and GRP96), calreticulin, and protein-disulfide isomerase were down-regulated under hypertonic stress.
...
PMID:Proteomic analysis of cellular response to osmotic stress in thick ascending limb of Henle's loop (TALH) cells. 1597 15
Metabolic changes, principally in intermediary metabolism and nitrogen excretion, were investigated in the marble swamp eel (Synbranchus marmoratus) after 15 and 45 days of artificially induced semi-aestivation. Glucose, glycogen, lactate, pyruvate, free amino acids, triglycerides, ammonia, urea, and urate contents were determined in liver, kidney, white muscle, heart, brain, and plasma. Lactate dehydrogenase, glutamate dehydrogenase,
malate dehydrogenase
, aspartate amino transferase, alanine amino transferase, glutamine synthase, ornithine carbamoyl transferase, and arginase enzymes were assayed. The teleost S. marmoratus maintained initial energetic demands by lipid oxidation. The course of normal oxidative processes was observed through tissue enzyme profiles. After the lipid stores were exhausted, the fish consumed body proteins. Constant values of hematocrit during induced semi-aestivation suggested that the
water
balance remained normal. Therefore, the surrounding
water
was probably did not trigger the semi-aestivation in this teleost. Decrease of ammonia and increase of renal urea synthesis after 45 days of semi-aestivation led to the assumption that an alternative form of eliminating ammonia exists. Metabolic changes entailed by starvation were proposed to explain the biosynthesis of small molecules involved in the semi-aestivation of S. marmoratus.
...
PMID:Metabolic adjustments during semi-aestivation of the marble swamp eel (Synbranchus marmoratus, Bloch 1795)--a facultative air breathing fish. 1609 34
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