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phylloquinone

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https://www.readbyqxmd.com/read/28530393/structural-factors-that-alter-the-redox-potential-of-quinones-in-cyanobacterial-and-plant-photosystem-i
#1
Keisuke Kawashima, Hiroshi Ishikita
Using the cyanobacterial and plant photosystem I (PSI) crystal structures and by considering the protonation states of all titratable residues, redox potentials (Em) of the two phylloquinones--A1A and A1B--were calculated. The calculated Em values were Em(A1A) = -773 mV and Em(A1B) = -818 mV for the plant PSI structure and Em(A1A) = -612 mV and Em(A1B) = -719 mV for the cyanobacterial PSI structure. Our analysis of the PSI crystal structures suggested that the side-chain orientations of Lys-B542 and Gln-B678 in the cyanobacterial crystal structure differ from these side-chain orientations in the plant crystal structure...
May 22, 2017: Biochemistry
https://www.readbyqxmd.com/read/28445289/vitamin-k-intake-and-the-risk-of-fractures-a-meta-analysis
#2
Guangliang Hao, Bei Zhang, Mingyong Gu, Chen Chen, Qiang Zhang, Guichun Zhang, Xuecheng Cao
The association between dietary vitamin K intake and the risk of fractures is controversial. Therefore we perform a meta-analysis of cohort or nested case-control studies to investigate the relationship between dietary vitamin K intake and the risk of fractures. A comprehensive search of PubMed and EMBASE (to July 11, 2016) was performed to identify cohort or nested case-control studies providing quantitative estimates between dietary vitamin K intake and the risk of fractures. Summary relative risk (RRs) with corresponding 95% confidence intervals (CIs) were pooled by using a random-effects model...
April 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28405861/pk-a-of-ubiquinone-menaquinone-phylloquinone-plastoquinone-and-rhodoquinone-in-aqueous-solution
#3
Ryo Hasegawa, Keisuke Saito, Tomohiro Takaoka, Hiroshi Ishikita
Quinones can accept two electrons and two protons, and are involved in electron transfer and proton transfer reactions in photosynthetic reaction centers. To date, the pK a of these quinones in aqueous solution have not been reported. We calculated the pK a of the initial protonation (Q(·-) to QH(·)) and the second protonation (QH(-) to QH2) of 1,4-quinones using a quantum chemical approach. The calculated energy differences of the protonation reactions Q(·-) to QH(·) and QH(-) to QH2 in the aqueous phase for nine 1,4-quinones were highly correlated with the experimentally measured pK a(Q(·-)/QH(·)) and pK a(QH(-)/QH2), respectively...
April 12, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28403946/vitamin-k-and-osteoporosis-myth-or-reality
#4
REVIEW
Andrea Palermo, Dario Tuccinardi, Luca D'Onofrio, Mikiko Watanabe, Daria Maggi, Anna Rita Maurizi, Valentina Greto, Raffaella Buzzetti, Nicola Napoli, Paolo Pozzilli, Silvia Manfrini
Vitamin K is a liposoluble vitamin. The predominant dietary form, phylloquinone or vitamin K1, is found in plants and green vegetables; whereas menaquinone, or vitamin K2, is endogenously synthesized by intestinal bacteria and includes several subtypes that differ in side chain length. Aside from its established role in blood clotting, several studies now support a critical function of vitamin K in improving bone health. Vitamin K is in fact required for osteocalcin carboxylation that in turn regulates bone mineral accretion; it seems to promote the transition of osteoblasts to osteocytes and also limits the process of osteoclastogenesis...
May 2017: Metabolism: Clinical and Experimental
https://www.readbyqxmd.com/read/28357617/interaction-of-various-types-of-photosystem-i-complexes-with-exogenous-electron-acceptors
#5
Anastasia A Petrova, Baina K Boskhomdzhieva, Georgy E Milanovsky, Olga A Koksharova, Mahir D Mamedov, Dmitry A Cherepanov, Alexey Yu Semenov
Interaction of photosystem I (PS I) complexes from cyanobacteria Synechocystis sp. PCC 6803 containing various quinones in the A1-site (phylloquinone PhQ in the wild-type strain (WT), and plastoquinone PQ or 2,3-dichloronaphthoquinone Cl 2 NQ in the menB deletion strain) and different numbers of Fe4S4 clusters (intact WT and FX-core complexes depleted of FA/FB centers) with external acceptors has been studied. The efficiency of interaction was estimated by measuring the light-induced absorption changes at 820 nm due to the reduction of the special pair of chlorophylls (P700(+)) by an external acceptor(s)...
March 29, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28356433/circulating-vitamin-k-is-inversely-associated-with-incident-cardiovascular-disease-risk-among-those-treated-for-hypertension-in-the-health-aging-and-body-composition-study-health-abc
#6
M Kyla Shea, Sarah L Booth, Daniel E Weiner, Tina E Brinkley, Alka M Kanaya, Rachel A Murphy, Eleanor M Simonsick, Christina L Wassel, Cees Vermeer, Stephen B Kritchevsky
Background: A role for vitamin K in coronary artery calcification (CAC), a subclinical manifestation of cardiovascular disease (CVD), has been proposed because vitamin K-dependent proteins, including the calcification inhibitor matrix Gla protein (MGP), are present in vascular tissue. Observational studies found that low circulating phylloquinone (vitamin K-1) was associated with increased CAC progression, especially in persons treated for hypertension. It is unknown whether hypertension treatment modifies this putative role of vitamin K in clinical CVD risk...
March 29, 2017: Journal of Nutrition
https://www.readbyqxmd.com/read/28352992/kinetic-modeling-of-electron-transfer-reactions-in-photosystem-i-complexes-of-various-structures-with-substituted-quinone-acceptors
#7
Georgy E Milanovsky, Anastasia A Petrova, Dmitry A Cherepanov, Alexey Yu Semenov
The reduction kinetics of the photo-oxidized primary electron donor P700 in photosystem I (PS I) complexes from cyanobacteria Synechocystis sp. PCC 6803 were analyzed within the kinetic model, which considers electron transfer (ET) reactions between P700, secondary quinone acceptor A1, iron-sulfur clusters and external electron donor and acceptors - methylviologen (MV), 2,3-dichloro-naphthoquinone (Cl2NQ) and oxygen. PS I complexes containing various quinones in the A1-binding site (phylloquinone PhQ, plastoquinone-9 PQ and Cl2NQ) as well as F X-core complexes, depleted of terminal iron-sulfur F A/F B clusters, were studied...
March 28, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28125283/plastoglobuli-plastid-microcompartments-with-integrated-functions-in-metabolism-plastid-developmental-transitions-and-environmental-adaptation
#8
Klaas J van Wijk, Felix Kessler
Plastoglobuli (PGs) are plastid lipoprotein particles surrounded by a membrane lipid monolayer. PGs contain small specialized proteomes and metabolomes. They are present in different plastid types (e.g., chloroplasts, chromoplasts, and elaioplasts) and are dynamic in size and shape in response to abiotic stress or developmental transitions. PGs in chromoplasts are highly enriched in carotenoid esters and enzymes involved in carotenoid metabolism. PGs in chloroplasts are associated with thylakoids and contain ∼30 core proteins (including six ABC1 kinases) as well as additional proteins recruited under specific conditions...
April 28, 2017: Annual Review of Plant Biology
https://www.readbyqxmd.com/read/28032259/role-of-the-nad-p-h-quinone-oxidoreductase-nqr-and-the-cytochrome-b-air12-in-controlling-superoxide-generation-at-the-plasma-membrane
#9
Catherine Biniek, Eiri Heyno, Jerzy Kruk, Francesca Sparla, Paolo Trost, Anja Krieger-Liszkay
The quinone reductase NQR and the b-type cytochrome AIR12 of the plasma membrane are important for the control of reactive oxygen species in the apoplast. AIR12 and NQR are two proteins attached to the plant plasma membrane which may be important for generating and controlling levels of reactive oxygen species in the apoplast. AIR12 (Auxin Induced in Root culture) is a single gene of Arabidopsis that codes for a mono-heme cytochrome b. The NADPH quinone oxidoreductase NQR is a two-electron-transferring flavoenzyme that contributes to the generation of O 2(•-) in isolated plasma membranes...
April 2017: Planta
https://www.readbyqxmd.com/read/28007557/the-phytol-phosphorylation-pathway-is-essential-for-the-biosynthesis-of-phylloquinone-which-is-required-for-photosystem-i-stability-in-arabidopsis
#10
Lei Wang, Qingwei Li, Aihong Zhang, Wen Zhou, Rui Jiang, Zhipan Yang, Huixia Yang, Xiaochun Qin, Shunhua Ding, Qingtao Lu, Xiaogang Wen, Congming Lu
Phytyl-diphosphate, which provides phytyl moieties as a common substrate in both tocopherol and phylloquinone biosynthesis, derives from de novo isoprenoid biosynthesis or a salvage pathway via phytol phosphorylation. However, very little is known about the role and origin of the phytyl moiety for phylloquinone biosynthesis. Since VTE6, a phytyl-phosphate kinase, is a key enzyme for phytol phosphorylation, we characterized Arabidopsis vte6 mutants to gain insight into the roles of phytyl moieties in phylloquinone biosynthesis and of phylloquinone in photosystem I (PSI) biogenesis...
January 9, 2017: Molecular Plant
https://www.readbyqxmd.com/read/27862054/determination-of-target-fat-soluble-micronutrients-in-rainbow-trout-s-muscle-and-liver-tissues-by-liquid-chromatography-with-diode-array-tandem-mass-spectrometry-detection
#11
Virginia Pérez Fernández, Salvatore Ventura, Pierpaolo Tomai, Roberta Curini, Alessandra Gentili
This paper describes an analytical approach, based on LC-diode array detector-MS/MS (LC-DAD-MS/MS), for characterizing the fat-soluble micronutrient fraction in rainbow trout (Oncorhynchus mykiss). Two different procedures were applied to isolate the analytes from liver and muscle tissue: overnight cold saponification to hydrolyze bound forms and to simplify the analysis; matrix solid-phase dispersion to avoid artifacts and to maintain unaltered the naturally occurring forms. Analytes were separated on a C30 analytical column by using a nonaqueous reversed mobile phase compatible with the atmospheric pressure chemical ionization...
March 2017: Electrophoresis
https://www.readbyqxmd.com/read/27846632/vitamin-k-metabolism-in-a-rat-model-of-chronic-kidney-disease
#12
Kristin M McCabe, Sarah L Booth, Xueyan Fu, Emilie Ward, Michael A Adams, Rachel M Holden
BACKGROUND: Patients with chronic kidney disease (CKD) have very high levels of uncarboxylated, inactive, extra-hepatic vitamin K-dependent proteins measured in circulation, putting them at risk for complications of vitamin K deficiency. The major form of vitamin K found in the liver is phylloquinone (K1). Menaquinone-4 (MK-4) is the form of vitamin K that is preferentially found in extra-hepatic tissues. METHODS: In the present study, we assessed tissue concentrations of K1 and MK-4 and the expression of vitamin K-related genes in a rat model of adenine-induced CKD...
2017: American Journal of Nephrology
https://www.readbyqxmd.com/read/27806562/purification-and-characterization-of-the-principal-antimutagenic-bioactive-as-ethoxy-substituted-phylloquinone-from-spinach-spinacea-oleracea-l-based-on-evaluation-in-models-including-human-lymphoblast-tk-cells
#13
Sanjeev Kumar, Suchandra Chatterjee, Jyoti Tripathi, Satyendra Gautam
During in vitro analysis, spinach (Spinacea oleracea L.) leaf extracts displayed varying antimutagenicity when analyzed in models including human lymphoblast (TK(+/-)) cell line (thymidine kinase gene mutation assay) and Escherichia coli MG1655 (rifampicin resistance assay) against chemically (ethyl methanesulfonate and 5-azacytidine) induced mutagenicity. Highest antimutagenicity was displayed by the quinone extract. The principal bioactive compound exhibited fluorescence in TLC at 366 nm (termed C4) resolved at Rf 0...
November 23, 2016: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/27733530/phylloquinone-intakes-and-food-sources-and-vitamin-k-status-in-a-nationally-representative-sample-of-irish-adults
#14
Aoife Hayes, Áine Hennessy, Janette Walton, Breige A McNulty, Alice J Lucey, Máiréad Kiely, Albert Flynn, Kevin D Cashman
BACKGROUND: Data from a nationally representative sample of 18- to 64-y-old Irish adults conducted in 1999 highlighted low phylloquinone intakes. That survey, however, did not include older adults (aged ≥65 y), a subgroup that is potentially at higher risk of low phylloquinone intakes, or a biomarker of vitamin K status. OBJECTIVES: The objectives of this work were to measure the phylloquinone intake and its adequacy and the serum percentage of undercarboxylated osteocalcin (%ucOC), a vitamin K status biomarker, in a nationally representative sample of Irish adults aged 18-90 y, and to compare these newer data on dietary phylloquinone in adults aged 18-64 y with those from the previous survey...
October 12, 2016: Journal of Nutrition
https://www.readbyqxmd.com/read/27732556/vitamin-k-plasma-levels-determination-in-human-health
#15
REVIEW
Maria Fusaro, Maurizio Gallieni, Maria Antonietta Rizzo, Andrea Stucchi, Pierre Delanaye, Etienne Cavalier, Rosa M A Moysés, Vanda Jorgetti, Giorgio Iervasi, Sandro Giannini, Fabrizio Fabris, Andrea Aghi, Stefania Sella, Francesco Galli, Valentina Viola, Mario Plebani
Vitamin K (phylloquinone or vitamin K1 and menaquinones or vitamin K2) plays an important role as a cofactor in the synthesis of hepatic blood coagulation proteins, but recently has also aroused an increasing interest for its action in extra-hepatic tissues, in particular in the regulation of bone and vascular metabolism. The accurate measurement of vitamin K status in humans is still a critical issue. Along with indirect assays, such as the undercarboxylated fractions of vitamin K-dependent proteins [prothrombin, osteocalcin (OC), and matrix gla protein], the direct analysis of blood levels of phylloquinone and menaquinones forms might be considered a more informative and direct method for assessing vitamin K status...
May 1, 2017: Clinical Chemistry and Laboratory Medicine: CCLM
https://www.readbyqxmd.com/read/27722902/vitamin-k-homologs-as-potential-biomarkers-for-disease-activity-in-patients-with-rheumatoid-arthritis
#16
Hani M Khojah, Sameh Ahmed, Mahran S Abdel-Rahman, Khaled M Alkhalil, Al-Badr Hamza
The aim of this study was to evaluate the possible role of vitamin K homologs as potential biomarkers for disease activity in patients with rheumatoid arthritis (RA). In this study, 42 patients with RA and 40 healthy controls were enrolled. Serum levels of vitamin K homologs were measured using a high-performance liquid chromatography-fluorescence method. Different biochemical and clinical markers for disease activity were measured and correlated with serum levels of vitamin K homologs. There were no significant differences between RA patients and healthy subjects in demographic data...
October 8, 2016: Journal of Bone and Mineral Metabolism
https://www.readbyqxmd.com/read/27715010/combined-measurement-of-6-fat-soluble-vitamins-and-26-water-soluble-functional-vitamin-markers-and-amino-acids-in-50-%C3%A2%C2%B5l-of-serum-or-plasma-by-high-throughput-mass-spectrometry
#17
Øivind Midttun, Adrian McCann, Ove Aarseth, Marit Krokeide, Gry Kvalheim, Klaus Meyer, Per Magne Ueland
Targeted metabolic profiling characterized by complementary platforms, multiplexing and low volume consumption are increasingly used for studies using biobank material. Using liquid-liquid extraction, we developed a sample workup suitable for quantification of 6 fat- and 26 water-soluble biomarkers. 50μL of serum/plasma was mixed with dithioerythritol, ethanol and isooctane/chloroform. The organic layer was used for analysis of the fat-soluble vitamins all-trans retinol (A), 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, α-tocopherol (E), γ-tocopherol (E) and phylloquinone (K1) by LC-MS/MS...
October 7, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27640076/vitamin-k-intake-and-all-cause-and-cause-specific-mortality
#18
Sabine R Zwakenberg, Nicole R den Braver, Anouk I P Engelen, Edith J M Feskens, Cees Vermeer, Jolanda M A Boer, W M Monique Verschuren, Yvonne T van der Schouw, Joline W J Beulens
BACKGROUND & AIMS: Vitamin K has been associated with various health outcomes, including non-fatal cardiovascular diseases (CVD) and cancer. However, little is known about the association between vitamin K intake and all-cause and cause specific mortality. This study aims to investigate the association between vitamin K intake and all-cause and cause-specific mortality. METHODS: This prospective cohort study included 33,289 participants from the EPIC-NL cohort, aged 20-70 years at baseline and recruited between 1993 and 1997...
August 30, 2016: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
https://www.readbyqxmd.com/read/27631574/stabilization-and-detection-of-hydrophylloquinone-as-di-o-methyl-derivative
#19
Rodrigo A C Sussmann, Marcilio M de Moraes, Gerardo Cebrián-Torrejón, Exequiel O Porta, Antonio Doménech-Carbó, Lydia F Yamaguchi, Alejandro M Katzin, Massuo J Kato
Phylloquinone is a redox active naphthoquinone involved in electron transport in plants. The function of this reduced form remains unclear due to its instability, which has precluded detection. Herein, a simple method that permits the stabilization of the reduced form of phylloquinone by di-O-methylation and HPLC detection is described.
October 15, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/27624160/laser-induced-acoustic-desorption-atmospheric-pressure-photoionization-via-vuv-generating-microplasmas
#20
Kevin Benham, Robert Hodyss, Facundo M Fernández, Thomas M Orlando
We demonstrate the first application of laser-induced acoustic desorption (LIAD) and atmospheric pressure photoionization (APPI) as a mass spectrometric method for detecting low-polarity organics. This was accomplished using a Lyman-α (10.2 eV) photon generating microhollow cathode discharge (MHCD) microplasma photon source in conjunction with the addition of a gas-phase molecular dopant. This combination provided a soft desorption and a relatively soft ionization technique. Selected compounds analyzed include α-tocopherol, perylene, cholesterol, phenanthrene, phylloquinone, and squalene...
November 2016: Journal of the American Society for Mass Spectrometry
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