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Query: EC:1.6.5.2 (
NQO1
)
6,196
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The fungicide dexon (p-dimethylaminobenzenediazosulfonate, Na-salt) inhibits the NADH oxidase activity of submitochondrial particles (
ETP
) from beef heart (semi-inhibition concentration 1.4 muM), while the succinate oxidase activity is unaffected. Measurements of the activity of several enzymatic partial reactions of the respiratory chain of
ETP
suggest that dexon acts directly on the flavine of NADH dehydrogenase. Soluble NADH-cytochrome c-oxidoreductase (MAHLER) and rotenone-insensitive NADH ubiquinone reductase are also inhibited by dexon. At low concentrations of dexon, inhibition of
ETP
starts slowly only after addition of NADH. Preincubation without NADH increases the amount of inhibition, but does not prevent the time delay. It is assumed that an electron flux through the respiratory chain, or reduction of flavine is prerequisite for the reaction of dexon with the action site. Furthermore, dexon inhibits the NADH dehydrogenase located at the outer surface of the inner membrane of plant mitochondria, accessible to extramitochondrial NADH and insensitive to rotenone, as has been shown on isolated mitochondria from cauliflower (Brassica oleracea L). In addition, dexon inhibits selectively the NADH dehydrogenase of the DT
diaphorase
(ERNSTER) from rat liver cytosol. In contrast, the dicoumarol-insensitive NADH dehydrogenase (ZINSMEYER et al.) from rat liver cytosol, the NADH-cytochrome b5-reductase (STRITTMATTER) from rat liver microsomes, the rotenone-insensitive NADH-cytochrome c-oxidoreductase of the outer membrane of rat liver mitochondria, soluble NADH-oxidase from Escherichia coli, and NADH-dehydrogenase from human erythrocytes are not inhibited. The results suggest that dexon is a group reagent to certain pyridine nucleotide-dependent flavine enzymes.
...
PMID:[Action of the systemic fungicide dexon on several NADH dehydrogenases]. 82 48
The selection of clones resistant to methionine antagonists was undertaken on baby hamster Kidney cells grown in a methionine free medium, supplemented with homocystine, folic acid and hydroxo-B12. Clones resistant to 30 mug/ml ethionine were isolated after mutagenesis at an induced mutation frequency of 2.3 X 10(-5). An ethionine resistant clone,
ETH
304, was extensively studied. The resistant cells excreted methionine in the culture medium and the intracellular pools of methionine and SAM were two to five times greater in the resistant clone than in the wild type cells. A semidominant ethionine resistant phenotype was observed in hybrids between the wild type and this resistant clone. Measurement of the specific activity of
menadione reductase
, B12 methyltransferase and ATP: L-methionine S-adenosyl-transferase in crude extracts of the wild type showed a repressive action of methionine on the level of the three enzymes. However, the ethionine resistant clone
ETH
304 was not modified in this function. Menadione reductase is feedback-inhibited by SAM in wild type cells. The enzyme of the ethionine resistant clone was significantly less sensitive to SAM. When a comparison of thermal stability was made between the wild type and ethionine resistant clone enzymes, it was found that the thermal stability of the latter was modified. Three other ethionine resistant clones, independantly isolated, were similarly affected in the properties of
menadione reductase
. These results suggest that the pathway of re-use of S-adenosyl homocysteine, produced during methylation reactions, is highly regulated by methionine and SAM.
...
PMID:Methionine metabolism in BHK cells: selection and characterization of ethionine resistant clones. 125 54
Oxidative stress and inflammation in neuron-glia system are key factors in the pathogenesis of neurodegenerative diseases. As synthetic drugs may cause side effects, natural products have gained recognition for the prevention or management of diseases. In this study, hot water (HE-HWA) and ethanolic (HE-
ETH
) extracts of the basidiocarps of
Hericium erinaceus
mushroom were investigated for their neuroprotective and anti-inflammatory activities against hydrogen peroxide (H
2
O
2
)-induced neurotoxicity in HT22 mouse hippocampal neurons and lipopolysaccharide (LPS)-induced BV2 microglial activation respectively. HE-
ETH
showed potent neuroprotective activity by significantly (
p
< 0.0001) increasing the viability of H
2
O
2
-treated neurons. This was accompanied by significant reduction in reactive oxygen species (ROS) (
p
< 0.05) and improvement of the antioxidant enzyme catalase (CAT) (
p
< 0.05) and glutathione (GSH) content (
p
< 0.01). Besides, HE-
ETH
significantly improved mitochondrial membrane potential (MMP) (
p
< 0.05) and ATP production (
p
< 0.0001) while reducing mitochondrial toxicity (
p
< 0.001), Bcl-2-associated X (Bax) gene expression (
p
< 0.05) and nuclear apoptosis (
p
< 0.0001). However, gene expression of Nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1) and NAD(P)H quinone dehydrogenase 1 (
NQO1
) were unaffected (
p
> 0.05). HE-
ETH
also significantly (
p
< 0.0001) reduced nitric oxide (NO) level in LPS-treated BV2 indicating an anti-inflammatory activity in the microglia. These findings demonstrated HE-
ETH
maybe a potential neuroprotective and anti-inflammatory agent in neuron-glia environment.
...
PMID:Lion's Mane Mushroom,
Hericium erinaceus
(Bull.: Fr.) Pers. Suppresses H
2
O
2
-Induced Oxidative Damage and LPS-Induced Inflammation in HT22 Hippocampal Neurons and BV2 Microglia. 3137 12
