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)

Heparin and quercetin induce capacitation in spermatozoa through membrane receptor binding and inhibition of Ca-ATPase of the plasma membrane, respectively. Although capacitation is energy intensive, ammonia from amino acid metabolism can inhibit respiration and Krebs cycle activity. The objective was to determine activities of key enzymes in bull spermatozoa that contribute to the redox state and supply energy for capacitation. Malate dehydrogenase (MDH-NAD(+)), alanine and aspartate aminotransferases (ALT, AST), and lactate dehydrogenase-X (LDH-X) were measured spectrophotometrically (340 nm); mean (+/-S.D.) activities in control spermatozoa were 7.65+/-1.67, 0.45+/-0.05 and 0.74+/-0.14x10(-2)U/10(8) spermatozoa for MDH-NAD(+), ALT and AST, respectively, and were 2.83+/-0.66U/10(8) spermatozoa for LDH-X. Heparin decreased (P<0.05) activities of MDH-NAD(+), ALT, AST and LDH-X (78, 53, 66 and 66% of control levels, respectively); we inferred that amino acid catabolism was decreased. Quercetin decreased (P<0.05) activities of MDH-NAD(+) and ALT (60 and 49% of control levels), but activities of AST and LDH-X were not significantly different from controls; apparently maintenance of LDH-X activity supplied pyruvate for cellular metabolism. The proportion of capacitated spermatozoa in controls (8.5+/-1.73%) was substantially increased (P<0.05) by treatment with either heparin (36.2+/-4.5%) or quercetin (32.8+/-4.7%), there was no significant difference among groups for acrosomal integrity and sperm viability. In conclusion, heparin- or quercetin-induced capacitation affected different metabolic pathways that modulated the redox state and oxidative metabolism in cryopreserved bovine spermatozoa.
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PMID:Heparin and quercitin generate differential metabolic pathways that involve aminotransferases and LDH-X dehydrogenase in cryopreserved bovine spermatozoa. 1708 43

Folding of substrate proteins inside the sequestered and hydrophilic GroEL-GroES cis cavity favors production of the native state. Recent studies of GroEL molecules containing volume-occupying multiplications of the flexible C-terminal tail segments have been interpreted to indicate that close confinement of substrate proteins in the cavity optimizes the rate of folding: the rate of folding of a larger protein, Rubisco (51 kDa), was compromised by multiplication, whereas that of a smaller protein, rhodanese (33 kDa), was increased by tail duplication. Here, we report that this latter effect does not extend to the subunit of malate dehydrogenase (MDH), also 33 kDa. In addition, single-ring versions of tail-duplicated and triplicated molecules, comprising stable cis complexes, did not produce any acceleration of folding of rhodanese or MDH, nor did they show significant retardation of the folding of Rubisco. Tail quadruplication produced major reduction in recovery of native protein with both systems, the result of strongly reduced binding of all three substrates. When steady-state ATPase of the tail-multiplied double-ring GroELs was examined, it scaled directly with the number of tail segments, with more than double the normal ATPase rate upon tail triplication. As previously observed, disturbance of ATPase activity of the cycling double-ring system, and thus of "dwell time" for the folding protein in the cis cavity, produces effects on folding rates. We conclude that, within the limits of the approximately 10% decrease of cavity volume produced by tail triplication, there does not appear to be an effect of "close confinement" on folding in the cis cavity.
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PMID:Perturbed ATPase activity and not "close confinement" of substrate in the cis cavity affects rates of folding by tail-multiplied GroEL. 1737 95

F172-8, an H(+)-ATPase-defective mutant of the glutamic acid-producing bacterium Corynebacterium glutamicum ATCC 14067, exhibits enhanced rates of glucose consumption and respiration compared to the parental strain when cultured in a biotin-rich medium with glucose as the carbon source. We conducted a comparative proteomic analysis to clarify the mechanism by which the enhanced glucose metabolism in this mutant is established using a proteome reference map for strain ATCC 14067. A comparison of the proteomes of the two strains revealed the up-regulated expression of the several important enzymes such as pyruvate kinase (Pyk), malate:quinone oxidoreductase (Mqo), and malate dehydrogenase (Mdh) in the mutant. Because Pyk activates glycolysis in response to cellular energy shortages in this bacterium, its increased expression may contribute to the enhanced glucose metabolism of the mutant. A unique reoxidation system has been suggested for NADH in C. glutamicum consisting of coupled reactions between Mqo and Mdh, together with the respiratory chain; therefore, the enhanced expression of both enzymes might contribute to the reoxidation of NADH during increased respiration. The proteomic analysis allowed the identification of unique physiological changes associated with the H(+)-ATPase defect in F172-8 and contributed to the understanding of the adaptations of C. glutamicum to energy deficiencies.
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PMID:A comparative proteomic approach to understand the adaptations of an H+ -ATPase-defective mutant of Corynebacterium glutamicum ATCC14067 to energy deficiencies. 1784 11

DnaK is a molecular chaperone that promotes cell survival during stress by preventing protein misfolding. The chaperone activity is regulated by nucleotide binding and hydrolysis events in the N-terminal ATPase domain, which in turn mediate substrate binding and release in the C-terminal substrate binding domain. In this study we determined that ATP hydrolysis was the rate limiting step in the ATPase cycle of Agrobacterium tumefaciens DnaK (Agt DnaK); however the data suggested that Agt DnaK had a significantly lower affinity for ATP than Escherichia coli DnaK. We show for the first time that Agt DnaK was very effective at preventing thermal aggregation of malate dehydrogenase (MDH) in a concentration dependent manner. This is in contrast to E. coli DnaK which was ineffective at preventing thermal aggregation of MDH. A mutant Agt DnaK-V431F, with a blocked hydrophobic pocket in the substrate binding domain, was unable to suppress the thermosensitivty of an E. coli dnaK103 deletion strain. However the mutation did not inhibit Agt DnaK-V431F from preventing the thermal aggregation of MDH. The oligomeric state of Agt DnaK was studied using size exclusion chromatography. We demonstrated that dilution of the Agt DnaK protein, the addition of ATP and the removal of the 10kDa C-terminal alpha-helical subdomain reduced higher order associations but did not abrogate dimerisation. Our research implies that the C-terminal alpha-helical subdomain is involved in higher order associations, while the substrate binding domain is possibly involved in dimerisation.
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PMID:The Agrobacterium tumefaciens DnaK: ATPase cycle, oligomeric state and chaperone properties. 1806 11

We have previously reported the association of a mutation (c.292G > A/p.V98I) in the human HSPD1 gene that encodes the mitochondrial Hsp60 chaperonin with a dominantly inherited form of hereditary spastic paraplegia. Here, we show that the purified Hsp60-(p.V98I) chaperonin displays decreased ATPase activity and exhibits a strongly reduced capacity to promote folding of denatured malate dehydrogenase in vitro. To test its in vivo functions, we engineered a bacterial model system that lacks the endogenous chaperonin genes and harbors two plasmids carrying differentially inducible operons with human Hsp10 and wild-type Hsp60 or Hsp10 and Hsp60-(p.V98I), respectively. Ten hours after shutdown of the wild-type chaperonin operon and induction of the Hsp60-(p.V98I)/Hsp10 mutant operon, bacterial cell growth was strongly inhibited. No globally increased protein aggregation was observed, and microarray analyses showed that a number of genes involved in metabolic pathways, some of which are essential for robust aerobic growth, were strongly up-regulated in Hsp60-(p.V98I)-expressing bacteria, suggesting that the growth arrest was caused by defective folding of some essential proteins. Co-expression of Hsp60-(p.V98I) and wild-type Hsp60 exerted a dominant negative effect only when the chaperonin genes were expressed at relatively low levels. Based on our in vivo and in vitro data, we propose that the major effect of heterozygosity for the Hsp60-(p.V98I) mutation is a moderately decreased activity of chaperonin complexes composed of mixed wild-type and Hsp60-(p.V98I) mutant subunits.
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PMID:The Hsp60-(p.V98I) mutation associated with hereditary spastic paraplegia SPG13 compromises chaperonin function both in vitro and in vivo. 1840 Jul 58

The amelioration effect of dietary high protein and vitamin C against stress was evaluated in spotted murrel, Channa punctatus, exposed to endosulfan. Two hundred and forty fish (average weight: 27.01 g/fish), distributed equally into 4 different groups (control, T(1), T(2), and T(3)), each with 6 replicates were fed with control (40% crude protein, CP and 0.1% vitamin C), T(1) (40% CP and 0.1% vitamin C), T(2) (50% CP and 0.1% vitamin C), and T(3) (50% CP and 0.2% vitamin C) diets for 90 days. Groups fed T(1), T(2), and T(3) diets were exposed to sublethal endosulfan concentration, whereas the control was maintained without endosulfan exposure. Results indicated significant reduction in the growth performance, survival, and activities of lactate dehydrogenase (liver and muscle), malate dehydrogenase (liver and muscle), enzymes of protein metabolism (aspartate amino transferase in liver and alanine amino transferase in liver and muscle), acetyl choline esterase (brain), alkaline phosphatase activity (liver), and ATPase (gill) enzymes of group fed control diet and exposed to endosulfan. However, endosulfan exposed fish fed high CP and vitamin C diet exhibited significant (P<0.05) improvement in their growth performance and metabolic enzyme activities. Further, high CP and vitamin C diet reduced endosulfan accumulation in the muscle. Overall results indicate that vitamin C (0.2%) supplementation in high CP (50%) diet improves growth, metabolism, and reduce endosulfan bioaccumulation in C. punctatus.
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PMID:Dietary high protein and vitamin C mitigates endosulfan toxicity in the spotted murrel, Channa punctatus (Bloch, 1793). 1932 96

Growth inhibition in acid soils due to Al stress affects crop production worldwide. To understand mechanisms in sensitive crops that are affected by Al stress, a proteomic analysis of primary tomato root tissue, grown in Al-amended and non-amended liquid cultures, was performed. DIGE-SDS-MALDI-TOF-TOF analysis of these tissues resulted in the identification of 49 proteins that were differentially accumulated. Dehydroascorbate reductase, glutathione reductase, and catalase enzymes associated with antioxidant activities were induced in Al-treated roots. Induced enzyme proteins associated with detoxification were mitochondrial aldehyde dehydrogenase, catechol oxidase, quinone reductase, and lactoylglutathione lyase. The germin-like (oxalate oxidase) proteins, the malate dehydrogenase, wali7 and heavy-metal associated domain-containing proteins were suppressed. VHA-ATP that encodes for the catalytic subunit A of the vacuolar ATP synthase was induced and two ATPase subunit 1 isoforms were suppressed. Several proteins in the active methyl cycle, including SAMS, quercetin 3-O-methyltransferase and AdoHcyase, were induced by Al stress. Other induced proteins were isovaleryl-CoA dehydrogenase and the GDSL-motif lipase hydrolase family protein. NADPH-dependent flavin reductase and beta-hydroxyacyl-ACP dehydratase were suppressed.
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PMID:Proteome changes induced by aluminium stress in tomato roots. 1982 Mar 57

Early Alzheimer's disease (EAD) is the intermediary stage between mild cognitive impairment (MCI) and late-stage Alzheimer's disease (AD). The symptoms of EAD mirror the disease advancement between the two phases. Dementia, memory deficits, and cognitive decline are more pronounced as the disease progresses. Oxidative stress in brain is reported in MCI and AD, including lipid peroxidation indexed by protein-bound 4-hydroxy-2-nonenal (HNE). There are limited data regarding the proteomics analysis of brain from subjects with EAD and even less concerning the possible relationship of EAD HNE-modified brain proteins with HNE-modified proteins in MCI and AD. Proteomics was utilized to investigate excessively HNE-bound brain proteins in EAD compared to those in control. These new results provide potentially valuable insight into connecting HNE-bound brain proteins in EAD to those previously identified in MCI and AD, since EAD is a transitional stage between MCI and late-stage AD. In total, six proteins were found to be excessively covalently bound by HNE in EAD inferior parietal lobule (IPL) compared to age-related control brain. These proteins play roles in antioxidant defense (manganese superoxide dismutase), neuronal communication and neurite outgrowth (dihydropyriminidase-related protein 2), and energy metabolism (alpha-enolase, malate dehydrogenase, triosephosphate isomerase, and F1 ATPase, alpha subunit). This study shows that there is an overlap of brain proteins in EAD with previously identified oxidatively modified proteins in MCI and late-stage AD. The results are consistent with the hypothesis that oxidative stress, in particular lipid peroxidation, is an early event in the progression of AD, and is the first to identify in EAD identical brain proteins previously identified as HNE-modified in MCI and late-state AD.
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PMID:Proteomic identification of HNE-bound proteins in early Alzheimer disease: Insights into the role of lipid peroxidation in the progression of AD. 1937 91

Hsp90 proteins are essential molecular chaperones regulating multiple cellular processes in distinct subcellular organelles. In this study, we report the functional characterization of a cDNA encoding endoplasmic reticulum (ER)-resident Hsp90 from orchardgrass (DgHsp90). DgHsp90 is a 2742bp cDNA with an open reading frame predicted to encode an 808 amino acid protein. DgHsp90 has a well conserved N-terminal ATPase domain and a C-terminal Hsp90 domain and ER-retention motif. Expression of DgHsp90 increased during heat stress at 35 degrees C or H(2)O(2) treatment. DgHsp90 also functions as a chaperone protein by preventing thermal aggregation of malate dehydrogenase (EC 1.1.1.37) and citrate synthase (EC 2.3.3.1). The intrinsic ATPase activity of DgHsp90 was inhibited by geldanamycin, an Hsp90 inhibitor, and the inhibition reduced the chaperone activity of DgHsp90. Yeast cells overexpressing DgHsp90 exhibited enhanced thermotolerance.
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PMID:Functional characterization of orchardgrass endoplasmic reticulum-resident Hsp90 (DgHsp90) as a chaperone and an ATPase. 1962 92

Compared to the group I chaperonins such as Escherichia coli GroEL, which facilitate protein folding, many aspects of the functional mechanism of archaeal group II chaperonins are still unclear. Here, we show that monomeric forms of archaeal group II chaperonin alpha and beta from Thermoplasma acidophilum may be purified stably and that these monomers display a strong AMPase activity in the presence of divalent ions, especially Co(2+) ion, in addition to ATPase and ADPase activities. Furthermore, other nucleoside phosphates (guanosine, cytidine, uridine, and inosine phosphates) in addition to adenine nucleotides were hydrolyzed. From analyses of the products of hydrolysis using HPLC, it was revealed that the monomeric chaperonin successively hydrolyzed the phosphoanhydride and phosphoester bonds of ATP in the order of gamma to alpha. This activity was strongly suppressed by point mutation of specific essential aspartic acid residues. Although these archaeal monomeric chaperonins did not alter the refolding of MDH, their novel versatile nucleotide hydrolysis activity might fulfill a new function. Western blot experiments demonstrated that the monomeric chaperonin subunits were also present in lysed cell extracts of T. acidophilum, and partially purified native monomer displayed Co(2+)-dependent AMPase activity.
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PMID:A potentially versatile nucleotide hydrolysis activity of group II chaperonin monomers from Thermoplasma acidophilum. 1972 44


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