A5071870549- Metal-Catalyzed Oxygenation Mechanisms
- Microbial bioremediation and biosurfactants
- Porphyrin and Phthalocyanine Chemistry
- Catalytic Processes in Materials Science
- Trace Elements in Health
- Photosynthetic Processes and Mechanisms
- Heavy Metal Exposure and Toxicity
- Pharmacogenetics and Drug Metabolism
- Various Chemistry Research Topics
- Advanced Photocatalysis Techniques
- Mass Spectrometry Techniques and Applications
- TiO2 Photocatalysis and Solar Cells
- Chemical Reactions and Isotopes
- Microbial metabolism and enzyme function
- CO2 Reduction Techniques and Catalysts
- Catalysis and Hydrodesulfurization Studies
- Hemoglobin structure and function
- Porphyrin Metabolism and Disorders
- Enzyme Catalysis and Immobilization
- Electrochemical Analysis and Applications
- Heme Oxygenase-1 and Carbon Monoxide
- Nanomaterials for catalytic reactions
- Electrocatalysts for Energy Conversion
- Plant Micronutrient Interactions and Effects
- Molecular Sensors and Ion Detection
Barnard College
2016-2025
Columbia University
2015-2025
Nottingham Trent University
2023
Birla Institute of Technology and Science, Pilani - Dubai Campus
2021
University College London
2018
University of Delaware
2017
University of Maine
2001-2016
Bates College
2005-2015
New York Proton Center
2015
Northwestern University
2014
Catalytic reduction of pyrolyzed biomass is required to remove oxygen and produce transportation fuels, but limited knowledge how hydrodeoxygenation (HDO) catalysts work stymies the rational design more efficient stable catalysts, which in turn limits deployment biofuels. This reports results from a novel study utilizing both isotopically labeled phenol (which models most recalcitrant components biofuels) with D2O DFT calculations provide insight into mechanism highly HDO catalyst, Ru/TiO2....
Alkane monooxygenase (AlkB) is the dominant enzyme that catalyzes oxidation of liquid alkanes in environment. Two recent structural models derived from cryo-electron microscopy (cryo-EM) reveal an unusual active site: a histidine-rich center binds two iron ions without bridging ligand. To ensure potential photoreduction and radiation damage are not responsible for absence ligand cryo-EM structures, spectroscopic methods needed. We present results extended X-ray absorption fine structure...
Summary Desulfatibacillum alkenivorans AK‐01 serves as a model organism for anaerobic alkane biodegradation because of its distinctive biochemistry and metabolic versatility. The D. genome provides blueprint understanding the genetic systems involved in metabolism including substrate activation, CoA ligation, carbon‐skeleton rearrangement decarboxylation. Genomic analysis suggested route to regenerate fumarate needed activation via methylmalonyl‐CoA predicted capability syntrophic...
Abstract Alkanes are the most energy-rich form of carbon and widely dispersed in environment. Their transformation by microbes represents a key step global cycle. Alkane monooxygenase (AlkB), membrane-spanning metalloenzyme, converts straight chain alkanes to alcohols first microbially-mediated degradation alkanes, thereby playing critical role cycling bioremediation oil. AlkB biodiversity is attributed its ability oxidize various lengths, while individual AlkBs target relatively narrow...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT.beta.-Halogenated-pyrrole porphyrins. Molecular structures of 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetramesitylporphyrin, nickel(II) and 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrinD. Mandon, P. Ochenbein, J. Fischer, R. Weiss, K. Jayaraj, N. Austin, A. Gold, S. White, O. Brigaud, Cite this: Inorg. Chem. 1992, 31, 11, 2044–2049Publication Date (Print):May 1, 1992Publication History Published online1 May...
Despite four additional electron-withdrawing substituents, the octahalogenated porphyrins 2 are more easily oxidized than their tetra-halogenated counterparts 1. This apparent paradox can be explained by structures of molecules: almost planar, whereas in 1 steric interactions minimized a saddle conformation, which makes these easier to oxidize.
Rieske dioxygenases catalyze the cis-dihydroxylation of a wide range aromatic compounds to initiate their biodegradation. The archetypal dioxygenase naphthalene 1,2-dioxygenase (NDOS) catalyzes dioxygenation form (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene. NDOS is composed three proteins: reductase, ferredoxin, and an α3β3 oxygenase (NDO). In each α subunit, NDO contains Fe2S2 cluster mononuclear iron site where substrate dihydroxylation occurs. also monooxygenase reactions for many...
OleT is a cytochrome P450 enzyme that catalyzes the removal of carbon dioxide from variable chain length fatty acids to form 1-alkenes. In this work, we examine binding and metabolic profile with shorter (n ≤ 12) can liquid transportation fuels. Transient kinetics product analyses confirm capably activates hydrogen peroxide substrates high-valent intermediate Compound I largely performs C-C bond scission. However, also produces alcohol side products using iron oxo chemistry commonly...
The canine transmissible venereal tumor (CTVT) is a clonally cancer that regresses spontaneously or after treatment with vincristine, but we know little about the regression mechanisms. We performed global transcriptional, methylation, and functional pathway analyses on serial biopsies of vincristine-treated CTVTs found occurs in sequential steps; activation innate immune system host epithelial tissue remodeling followed by infiltration tumor, arrest cell cycle, repair damage. identified...
Purified alkane monooxygenase (AlkB) from Fontimonas thermophila (FtAlkB) catalyzes the defluorination of 1-fluorooctane, producing octanal, which is partially reduced under reaction conditions to generate 1-octanol. This occurs preferentially at monofluorinated methyl group, with only a minor amount oxidation nonfluorinated end molecule. The dehalogenation chemistry specific as neither 1-chlorooctane or 1-bromooctane are dehalogenated an appreciable extent. Furthermore, P. putida cells...
Norcarane is a valuable mechanistic probe for enzyme-catalyzed hydrocarbon oxidation reactions because different products or product distributions result from concerted, radical, and cation based reactions. Soluble methane monooxygenase (sMMO) Methylosinus trichosporium OB3b catalyzes the of norcarane to afford 3-hydroxymethylcyclohexene 3-cycloheptenol, compounds characteristic radical cationic intermediates, respectively, in addition 2- 3-norcaranols. Past single turnover transient kinetic...
The tetraaza macrocycles 2-oxa-3-oxotetramesitylporphine (|H(2) 1|) and 2-oxa-3-oxotetrakis(2,6-dichlorophenyl)porphine 2|) the corresponding iron complexes (|Fe(III)(X) 1| |Fe(III)(X) 2|; X= Cl(-), OH(-), or SO(3)CF(3)(-)) have been synthesized. These are derived from porphyrins by transformation of one pyrrole ring to an oxazolone ring. resulting lactone functionality serves restrict but not completely block pi-conjugation around periphery. thus share properties with both chlorins. ferric...
A purified and highly active form of the non-heme diiron hydroxylase AlkB was investigated using diagnostic probe substrate norcarane. The reaction afforded C2 (26%) C3 (43%) hydroxylation desaturation products (31%). Initial C-H cleavage at led to 7% 19% 3-hydroxymethylcyclohexene, a rearrangement product characteristic radical pathway. deuterated analogue, 3,3,4,4-norcarane-d(4), drastically reduced amounts alcohol (8%) (5%), while rearranged now major (65%). This change in ratios...
Isothermal titration calorimetry (ITC) was used to quantify the thermodynamics of Pb(2+) and Zn(2+) binding metallothionein-3 (MT-3). binds zinc-replete Zn7MT-3 displacing each zinc ion with a similar change in free energy (ΔG) enthalpy (ΔH). EDTA chelation measurements Pb7MT-3 reveal that both metal ions are extracted tri-phasic process, indicating they bind protein three populations different thermodynamics. Metal is entropically favoured, an enthalpic penalty reflects cost cysteine...
The surface reactivity of TiO2 is often governed by hydroxyl groups. Fourier transform infrared (FTIR) spectroscopy the most commonly used method to study hydroxyls. However, interpretation observed bands powder samples not straightforward. In this work, we propose a facet-specific assignment hydroxyls pyrogenic (commonly known as P25 and P90) comparison between experimentally FTIR P90, rutile, anatase with calculated vibrational frequencies for well-defined facets using density functional...
Understanding and quantifying how the active sites in supported metal catalysts can be modified are critical for rationally designing catalysts. This problem is particularly complex reactions that occur at metal–support interface (MSI) because of multiple chemistries associated with support. In this study, we used oxidation substituted benzyl alcohol over Au/TiO2 Au/Al2O3 to probe MSI chemistry. Substituents impacted substrate binding, deprotonation, rate-limiting transfer a hydride from Au,...