نتایج جستجو برای: metalloporphyrin

تعداد نتایج: 401  

Journal: :Chemistry & biology 2014
Gil G Westmeyer Yelena Emer Jutta Lintelmann Alan Jasanoff

The ability to map patterns of gene expression noninvasively in living animals could have impact in many areas of biology. Reporter systems compatible with MRI could be particularly valuable, but existing strategies tend to lack sensitivity or specificity. Here we address the challenge of MRI-based gene mapping using the reporter enzyme secreted alkaline phosphatase (SEAP), in conjunction with ...

2012
Sayed Yahya Kazemi Seyed Mohammad Abedirad

The present work deals with an attempt to study the effect of human and bovine serum albumin on kinetic parameters of chemiluminescence of luminol-hydrogen peroxide system catalyzed by manganese tetrasulfonatophenyl porphyrin (MnTSPP). The investigated parameters involved pseudo-first-order rise and fall rate constant for the chemiluminescence burst, maximum level intensity, time to reach maxim...

Journal: :Journal of the American Chemical Society 2010
Venkata Krishnan Andrey Tronin Joseph Strzalka H Christopher Fry Michael J Therien J Kent Blasie

"Push-pull" chromophores based on extended pi-electron systems have been designed to exhibit exceptionally large molecular hyperpolarizabilities. We have engineered an amphiphilic four-helix bundle peptide to vectorially incorporate such hyperpolarizable chromophores having a metalloporphyrin moiety, with high specificity into the interior core of the bundle. The amphiphilic exterior of the bun...

Journal: :American journal of biomedical sciences 2009
Chen-Zhong Li Subbiah Alwarappan Wenbo Zhang Nikki Scafa Xueji Zhang

Nitric oxide (NO) has been considered as an important bio-regulatory molecule in the physiological process. All the existing methods often employed for NO measurement are mainly indirect and not suitable for in vivo conditions. In this paper, we report a systematic study of electrocatalytic NO reduction by comparing the redox properties of NO at carbon microelectrodes functionalized by Fe, Mn a...

Journal: :Journal of agricultural and food chemistry 2003
Catherine Caris-Veyrat Antje Schmid Michel Carail Volker Böhm

The aim of this study was to produce in vitro oxidation products of lycopene, which could be possible in vivo metabolites. An oxidation of lycopene with potassium permanganate gave a range of lycopene degradation compounds resulting from the oxidative cleavage of one or two carbon-carbon double bonds. Eleven apo-lycopenals/ones and six apo-carotendials were obtained and tentatively characterize...

Journal: :Blood 1983
S Sassa G S Drummond S E Bernstein A Kappas

Tin-protoporphyrin is a potent competitive inhibitor of heme oxygenase both in vivo in animals and in vitro in isolated enzyme preparations, and when administered to neonatal rats, prevents the development of postnatal hyperbilirubinemia. In this study we examined the effect of the metalloporphyrin on the activity of heme oxygenase in liver, kidney, and spleen, and on the level of bilirubin in ...

Journal: :Physical review letters 2009
Emad F Aziz Niklas Ottosson Sébastien Bonhommeau Nora Bergmann Wolfgang Eberhardt Majed Chergui

Soft-x-ray absorption spectroscopy at the L_{2,3} edge of the iron center in bovine hemoglobin and hemin under physiological conditions is reported for the first time. Spectra of the same compounds in solid form are presented for comparison. Striking differences in the electronic structure of the metalloporphyrin are observed between the liquid and solid compounds. We unambiguously show that he...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1989
C M Drain B Christensen D Mauzerall

Photoformation of metalloporphyrin cations in a lipid bilayer increases the ionic currents of negative and decreases those of positive hydrophobic ions. At low concentrations of the mobile hydrophobic ion, a 30% change in conductivity is observed that decreases with increasing concentration of positive tetraphenylphosphonium ion and increases drastically with increasing concentration of negativ...

Journal: :Nucleic acids research 1991
G Pratviel M Pitié J Bernadou B Meunier

Cationic manganese-porphyrin complexes, free or targetted with an intercalating agent, are able to cleave DNA using oxygen atom donors like potassium monopersulfate or magnesium monoperphthalate as coreactants. Detailed studies of the cleavage of calf thymus DNA, before and after a heating step, show that free bases and 5-methylene-2-furanone are the main reaction products, indicating that hydr...

Journal: :Talanta 1994
E Bakker E Malinowska R D Schiller M E Meyerhoff

The role of lipophilic anionic and cationic additives on the potentiometric anion selectivities of polymer membrane electrodes prepared with various metalloporphyrins as anion selective ionophores is examined. The presence of lipophilic anionic sites (e.g. tetraphenylborate derivatives) is shown to enhance the non-Hofmeister anion selectivities of membranes doped with In(III) and Sn(IV) porphyr...

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