Amino acids located in the outer-sphere of the trinuclear copper center in a multicopper oxidase, CueO as the putative electron donor in the four-electron reduction of dioxygen

Optical activity of the achiral cation [Co(NH3)6]3+ is induced both by (S)-AsnONa and (S)-GlnONa, as shown by a negative Cotton effect in the 1A1g → 1T1g transition region. An outer-sphere interaction by three-point attachment of the amides can explain the fact that substitution reaction of [Co(NH3)6]3+ with the mentioned amides in an alkaline medium is unusually slow as compared with other amino acids.

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Paramagnetic NMR Spectroscopy of a Tri-Nuclear Copper Center from a Multicopper Oxidase, Laccase

Biophysical Journal ◽

10.1016/j.bpj.2020.11.675 ◽

2021 ◽

Vol 120 (3) ◽

pp. 76a

Author(s):

Rubin Dasgupta

Keyword(s):

Nmr Spectroscopy ◽

Multicopper Oxidase ◽

Paramagnetic Nmr ◽

Copper Center

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ELECTRON DONORS AND COFAGTORS FOR DENITRIFIGATION BY PSEUDOMONAS PERFECTOMARINUS

Canadian Journal of Microbiology ◽

10.1139/m63-105 ◽

1963 ◽

Vol 9 (6) ◽

pp. 799-807 ◽

Cited By ~ 10

Author(s):

Martha Rhodes ◽

Audrey Best ◽

W. J. Payne

Keyword(s):

Amino Acids ◽

Electron Donor ◽

Electron Donors ◽

Resting Cells ◽

Test Compound ◽

Whole Cell ◽

Minimal Media

Pseudomonas perfectomarinus released nitrogen fiom nitrate in media containing a variety of amino acids, pyruvate, or urea, but only if these minimal media were supplemented with glucose or, preferably, citrate. L-Arabinose (and to a lesser degree, D-arabinose) served as electron donor in combination with glucose or citrate, whereas other sugars did not. Asparagine, however, was the most effective oxidizable substrate tested and was the only test compound supporting denitrification without supplementary glucose or citrate. Mano-metric experiments revealed that adapted resting cells liberated nitrogen very rapidly with asparagine but less rapidly with citrate. Furthermore, cell-free extracts of adapted bacteria denitrified nitrate when provided with these substrates. Flavine mononucleotide was more effective as a stimulatory cofactor for denitrification than flavine adenine dinucleotide in whole-cell experiments, but not with cell-free extracts. Experiments with dialyzed cell-free extracts revealed that the enzymes which oxidized asparagine and citrate (or actually isocitrate) were linked with triphosphopyridine nucleotide. Additional experiments with cell-free extracts revealed that oxidation of reduced triphosphopyridine nucleotide was enzymatically linked with flavine mononucleotide.

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Probing the Role of Axial Methionine in the Blue Copper Center of Azurin with Unnatural Amino Acids

Journal of the American Chemical Society ◽

10.1021/ja029699u ◽

2003 ◽

Vol 125 (29) ◽

pp. 8760-8768 ◽

Cited By ~ 69

Author(s):

Steven M. Berry ◽

Martina Ralle ◽

Donald W. Low ◽

Ninian J. Blackburn ◽

Yi Lu

Keyword(s):

Amino Acids ◽

Unnatural Amino Acids ◽

Blue Copper ◽

Copper Center

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Molybdenum Nitrogenase Catalyzes the Reduction and Coupling of CO to Form Hydrocarbons

Journal of Biological Chemistry ◽

10.1074/jbc.m111.229344 ◽

2011 ◽

Vol 286 (22) ◽

pp. 19417-19421 ◽

Cited By ~ 70

Author(s):

Zhi-Yong Yang ◽

Dennis R. Dean ◽

Lance C. Seefeldt

Keyword(s):

Amino Acids ◽

Partial Pressure ◽

Small Molecules ◽

Wild Type ◽

Fischer Tropsch ◽

Hydrocarbon Production ◽

Mofe Protein ◽

Femo Cofactor ◽

Electron Reduction ◽

The Relationship

The molybdenum-dependent nitrogenase catalyzes the multi-electron reduction of protons and N2 to yield H2 and 2NH3. It also catalyzes the reduction of a number of non-physiological doubly and triply bonded small molecules (e.g. C2H2, N2O). Carbon monoxide (CO) is not reduced by the wild-type molybdenum nitrogenase but instead inhibits the reduction of all substrates catalyzed by nitrogenase except protons. Here, we report that when the nitrogenase MoFe protein α-Val70 residue is substituted by alanine or glycine, the resulting variant proteins will catalyze the reduction and coupling of CO to form methane (CH4), ethane (C2H6), ethylene (C2H4), propene (C3H6), and propane (C3H8). The rates and ratios of hydrocarbon production from CO can be adjusted by changing the flux of electrons through nitrogenase, by substitution of other amino acids located near the FeMo-cofactor, or by changing the partial pressure of CO. Increasing the partial pressure of CO shifted the product ratio in favor of the longer chain alkanes and alkenes. The implications of these findings in understanding the nitrogenase mechanism and the relationship to Fischer-Tropsch production of hydrocarbons from CO are discussed.

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Reduction of nitroblue tetrazolium to formazan by folic acid

Chemical Papers ◽

10.2478/s11696-013-0495-5 ◽

2014 ◽

Vol 68 (5) ◽

Cited By ~ 2

Author(s):

Cesare Achilli ◽

Stefania Grandi ◽

Annarita Ciana ◽

Cesare Balduini ◽

Giampaolo Minetti

Keyword(s):

Amino Acids ◽

Folic Acid ◽

Carboxylic Acid ◽

Glutamic Acid ◽

Electron Donor ◽

The Other ◽

Nitroblue Tetrazolium ◽

Donor Moiety

AbstractThe reduction of nitroblue tetrazolium (NBT) to formazan by folic acid, N-(4-aminobenzoyl) glutamic acid, and other amino acids was studied in this paper. The reduction involves only one of the two tetrazolium rings of NBT. The reaction is considerably more rapid with folic acid and N-(4-aminobenzoyl) glutamic acid than with the other amino acids under study. The electron donor moiety appears to be the carboxylic acid in the alpha position. N-ethyl-N′(3-dimethylaminopropyl) carbodiimide notably increases the rate of the reaction and promotes the reduction of both tetrazolium rings.

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Synthesis and anticancer activity of two highly water-soluble and ionic Pt(IV) complexes as prodrugs for Pt(II) anticancer drugs

10.21203/rs.3.rs-839613/v1 ◽

2021 ◽

Author(s):

Anli Gao ◽

Yaxi Wu ◽

Jing Jiang ◽

Hongyu Gong ◽

Juan Yu ◽

...

Keyword(s):

Anticancer Activity ◽

Water Solubility ◽

Human Cancer ◽

Outer Sphere ◽

Human Colon ◽

Water Soluble ◽

Human Cancer Cell Lines ◽

Biological Tests ◽

Electron Reduction

Abstract Two new Pt(IV) complexes featuring mesylate as outer sphere anions, cis,trans,cis-[PtCl2(OH2)2 (NH3)2](CH3SO3)2 (SPt-1) and cis,trans,cis-[PtCl2(OH2)2((1R,2R-DACH)](CH3SO3)2 (SPt-2) were synthesized, and characterized by elemental analysis, 1H- and 13C-NMR,IR, and ESI-MS. Both complexes have excellent water-solubility and high molar conductivity as well as good water-stability. They exhibit an irreversible two-electron reduction event with the peak potentials (Ep) for the processes being − 0.39 V and − 0.64 V for SPt-1 and 0.09 V and − 0.52 V for SPt-2. The biological tests reveal that SPt-2 possesses high in vitro anticancer activity against three human cancer cell lines and its overall anticancer activity is slightly greater than that of oxaliplatin, whereas SPt-1 is less active than cisplatin. Moreover, the antitumor efficacy of SPt-2 on human colon carcinoma HCT-116 xenografts in nude mice is also greater than that of oxaliplatin, suggesting SPt-2 deserves further evaluation as a prodrug for oxaliplatin.

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