Redox Potentials and Quinone Reductase Activity ofl-Aspartate Oxidase fromEscherichia coli†

Two new secondary metabolites, svalbamides A (1) and B (2), were isolated from a culture extract of Paenibacillus sp. SVB7 that was isolated from surface sediment from a core (HH17-1085) taken in the Svalbard archipelago in the Arctic Ocean. The combinational analysis of HR-MS and NMR spectroscopic data revealed the structures of 1 and 2 as being lipopeptides bearing 3-amino-2-pyrrolidinone, d-valine, and 3-hydroxy-8-methyldecanoic acid. The absolute configurations of the amino acid residues in svalbamides A and B were determined using the advanced Marfey’s method, in which the hydrolysates of 1 and 2 were derivatized with l- and d- forms of 1-fluoro-2,4-dinitrophenyl-5-alanine amide (FDAA). The absolute configurations of 1 and 2 were completely assigned by deducing the stereochemistry of 3-hydroxy-8-methyldecanoic acid based on DP4 calculations. Svalbamides A and B induced quinone reductase activity in Hepa1c1c7 murine hepatoma cells, indicating that they represent chemotypes with a potential for functioning as chemopreventive agents.

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Anaerobic NADH-Fumarate Reductase System Is Predominant in the Respiratory Chain of Echinococcus multilocularis, Providing a Novel Target for the Chemotherapy of Alveolar Echinococcosis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00378-07 ◽

2007 ◽

Vol 52 (1) ◽

pp. 164-170 ◽

Cited By ~ 40

Author(s):

Jun Matsumoto ◽

Kimitoshi Sakamoto ◽

Noriko Shinjyo ◽

Yasutoshi Kido ◽

Nao Yamamoto ◽

...

Keyword(s):

Respiratory Chain ◽

Echinococcus Multilocularis ◽

Alveolar Echinococcosis ◽

Reductase Activity ◽

Mitochondrial Respiratory Chain ◽

Quinone Reductase ◽

Fumarate Reductase ◽

Electron Mediator ◽

Mitochondrial Fractions ◽

Mitochondrial Respiratory

ABSTRACT Alveolar echinococcosis, which is due to the massive growth of larval Echinococcus multilocularis, is a life-threatening parasitic zoonosis distributed widely across the northern hemisphere. Commercially available chemotherapeutic compounds have parasitostatic but not parasitocidal effects. Parasitic organisms use various energy metabolic pathways that differ greatly from those of their hosts and therefore could be promising targets for chemotherapy. The aim of this study was to characterize the mitochondrial respiratory chain of E. multilocularis, with the eventual goal of developing novel antiechinococcal compounds. Enzymatic analyses using enriched mitochondrial fractions from E. multilocularis protoscoleces revealed that the mitochondria exhibited NADH-fumarate reductase activity as the predominant enzyme activity, suggesting that the mitochondrial respiratory system of the parasite is highly adapted to anaerobic environments. High-performance liquid chromatography-mass spectrometry revealed that the primary quinone of the parasite mitochondria was rhodoquinone-10, which is commonly used as an electron mediator in anaerobic respiration by the NADH-fumarate reductase system of other eukaryotes. This also suggests that the mitochondria of E. multilocularis protoscoleces possess an anaerobic respiratory chain in which complex II of the parasite functions as a rhodoquinol-fumarate reductase. Furthermore, in vitro treatment assays using respiratory chain inhibitors against the NADH-quinone reductase activity of mitochondrial complex I demonstrated that they had a potent ability to kill protoscoleces. These results suggest that the mitochondrial respiratory chain of the parasite is a promising target for chemotherapy of alveolar echinococcosis.

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Variation of glucosinolates and quinone reductase activity among different varieties of Chinese kale and improvement of glucoraphanin by metabolic engineering

Food Chemistry ◽

10.1016/j.foodchem.2014.07.073 ◽

2015 ◽

Vol 168 ◽

pp. 321-326 ◽

Cited By ~ 20

Author(s):

Hongmei Qian ◽

Bo Sun ◽

Huiying Miao ◽

Congxi Cai ◽

Chaojiong Xu ◽

...

Keyword(s):

Metabolic Engineering ◽

Reductase Activity ◽

Quinone Reductase ◽

Chinese Kale

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The In Vivo Effects of Oral Anticoagulants in Man: Comparison Between Liver and Non-Hepatic Tissues

Thrombosis and Haemostasis ◽

10.1055/s-0038-1642744 ◽

1988 ◽

Vol 59 (02) ◽

pp. 147-150 ◽

Cited By ~ 3

Author(s):

Marian de Boer-van den Berg ◽

Henk H W Thijssen ◽

Cees Vermeer

Keyword(s):

Vitamin K ◽

Reductase Activity ◽

Oral Anticoagulant Therapy ◽

Oral Anticoagulants ◽

Quinone Reductase ◽

Hepatic Microsomes ◽

Precursor Proteins ◽

Epoxide Reductase ◽

In Vivo Effects

SummaryThe in vivo effects of oral anticoagulant therapy with 4–hydroxycoumarins on various vitamin K–dependent enzyme systems in man were compared. In hepatic microsomes obtained from donors who has been treated with 4–hydroxycoumarins for more than 6 months, the vitamin K 2,3 epoxide reductase activity and the DTT–dependent vitamin K quinone reductase activity were diminished to 35% and 20% of the corresponding normal values. In the non–hepatic tissues, only a small decrease in vitamin K 2,3 epoxide reductase activity could be demonstrated, while no differences were found in the vitamin K quinone reductase activities. In none of the tissues a significant increase of non–carboxylated precursor proteins was observed, whereas also vitamin K hydroquinone–dependent carboxylase activities seemed to be unaffected by the anticoagulant treatment.

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