Heuristic Considerations Suggesting a Role for Electron Pairing in Thermodynamically Consistent Pathways of Enzyme Catalysis

1978 ◽  
Vol 33 (10) ◽  
pp. 1206-1209 ◽  
Author(s):  
Michael Conrad
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Complex Formation ◽  
Enzyme Catalysis ◽  
Pairing Interaction ◽  
Electron Pairing ◽  
Hypothetical Reaction

Abstract Nuclear motions accompanying enzyme catalysis are described in terms of a hypothetical reaction mechanism in which instabilities of electronic structure arise from short-lived pairing resonances of parallel spin electrons. A pairing interaction is proposed which has its basis in confinement constraints imposed by complex formation.

scholarly journals Enzymatic Synthesis of Muconic Acid-Based Polymers: Trans, Trans-Dimethyl Muconate and Trans, β-Dimethyl Hydromuconate

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2498
Author(s):  
Dina Maniar ◽  
Csaba Fodor ◽  
Indra Karno Adi ◽  
Albert J. J. Woortman ◽  
Jur van Dijken ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Renewable Resources ◽  
Enzymatic Synthesis ◽  
Enzyme Catalysis ◽  
Unsaturated Polyester ◽  
Chain Extension ◽  
Side Reactions ◽  
Muconic Acid ◽  
Thermal Stabilities ◽  
Polyester Resins

The vast majority of commodity polymers are acquired from petrochemical feedstock, and these resources will plausibly be depleted within the next 100 years. Therefore, the utilization of carbon-neutral renewable resources for the production of polymers is crucial in modern green chemistry. Herein, we report an eco-friendly strategy that uses enzyme catalysis to design biobased unsaturated (co)polyesters from muconic acid derivatives. This method is an attractive pathway for the production of well-defined unsaturated polyesters with minimum side reactions. A suite of characterization techniques was performed to probe the reaction mechanism and properties of the obtained polyesters. It is rationalized that the alkene functionality of the muconate monomers plays an important role in the enzyme catalysis mechanism. The rendered polyesters possessed excellent thermal stabilities and unreacted alkene functionality that can consecutively undergo chain extension, copolymerization, or act as an anchor for other functional groups. These properties open new avenues in the fields of unsaturated polyester resins and photosensitive coatings.

Synthesis, electronic structure, and complex formation of simple 1,1,4,4-tetrathiabutadienes

1981 ◽  
pp. 829 ◽  
Author(s):  
Daniel J. Sandman ◽  
Glenn D. Zoski ◽  
W. Andrew Burke ◽  
Gregory P. Hamill ◽  
Gerald P. Ceasar ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Complex Formation

scholarly journals Study of Interaction between Tigecycline and Sulbactam

2019 ◽  
pp. 1-9
Author(s):  
Hakan Sezgin Sayiner ◽  
Fatma Genç ◽  
Fatma Kandemirli
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Peripheral Neuropathy ◽  
Drug Interactions ◽  
Reaction Mechanisms ◽  
Bond Formation ◽  
Therapeutic Drug ◽  
Energetic Condition ◽  
Biochemical Systems ◽  
Semi Empirical

Drug interactions can have desired, reduced or unwanted effects. The probability of interactions increases with the number of drugs taken. Side effects or therapeutic drug interactions can increase or decrease the effects of one or two drugs. Failure may result from clinically meaningful interactions. Clinicians rarely use foreseeable drug-drug interactions to produce the desired therapeutic effect. For example, when we consider two drugs each causing, peripheral neuropathy increases the likelihood of neuropathy occurrence. In this study geometry optimizations of tigecycline and sulbactam drugs and their combination have been carried out with the evaluation of B3LYP/6-311G (d, p), B3LYP/6-311G (2d, 2p) levels, and the reaction mechanism at semi empirical PM6, which was parameterized for biochemical systems and B3LYP/6-311G (d,p) levels. The main objective of the study is to understand the interaction ofsulbactam with tigecycline, to describe energetic condition of bond formation and electronic structure (orders of the broken and formed bonds). The reaction mechanisms of sulbactam with tigecycline have been studied as stepwise and concerted mechanisms using semi-empircal PM6 and B3LYP/6-311G (d,p) levels.

Reactivity of Metal Carbenes with Olefins: Theoretical Insights on the Carbene Electronic Structure and Cyclopropanation Reaction Mechanism

2018 ◽  
Vol 122 (6) ◽  
pp. 1702-1712 ◽  
Author(s):  
E. de Brito Sá ◽  
A. Rimola ◽  
L. Rodríguez-Santiago ◽  
M. Sodupe ◽  
X. Solans-Monfort
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Metal Carbenes

CO2 conversion to methanol on Cu(i) oxide nanolayers and clusters: an electronic structure insight into the reaction mechanism

2015 ◽  
Vol 17 (16) ◽  
pp. 11088-11094 ◽  
Author(s):  
Ellie L. Uzunova ◽  
Nicola Seriani ◽  
Hans Mikosch
Keyword(s):  
Electronic Structure ◽  
Reaction Mechanism ◽  
Formic Acid ◽  
Co2 Conversion ◽  
Insight Into

The CO2 hydrogenation to methanol using dissociated water as the hydrogen source proceeds via stable carboxyl, formic acid and formaldehyde intermediates.

Studies of oxidations by fenton's reagent using redox titration. V. Effect of complex formation on reaction mechanism

1973 ◽  
Vol 26 (5) ◽  
pp. 1021 ◽  
Author(s):  
DL Ingles
Keyword(s):  
Reaction Mechanism ◽  
Complex Formation ◽  
Hydroxyl Radical ◽  
Butyl Alcohol ◽  
Fenton’S Reagent ◽  
Redox Titration ◽  
Fenton's Reagent ◽  
Free Hydroxyl ◽  
Electron Transfers ◽  
H2o2 System

The effect of complex formation on the oxidation of substrate in the Fe2+-H2O2 system has been studied. t-Butyl alcohol which is normally oxidized to the dimer, 2,5-dimethylhexane-2,5-diol, by Fenton's reagent has been used as a probe for the presence of free hydroxyl radical. ��� It is shown that when suitable complexes are formed substrates are not oxidized by free hydroxyl radical. Instead, new mechanisms involving one- and two-electron transfers within a substrate-ferrous ion-peroxide complex are proposed.

scholarly journals THE 3d-TO-4s-BY-2p HIGHWAY TO SUPERCONDUCTIVITY IN CUPRATES

2002 ◽  
Vol 16 (30) ◽  
pp. 4577-4585 ◽  
Author(s):  
TODOR M. MISHONOV ◽  
JOSEPH O. INDEKEU ◽  
EVGENI S. PENEV
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
High Temperature Superconductors ◽  
Electron Exchange ◽  
Theoretical Physics ◽  
Pairing Interaction ◽  
Electron Pairing

High-temperature superconductors are nowadays found in great variety and hold technological promise. It is still an unsolved mystery that the critical temperature T c of the basic cuprates is so high. The answer might well be hidden in a conventional corner of theoretical physics, overlooked in the recent hunt for exotic explanations of new effects in these materials. A forgotten intra-atomic s–d two-electron exchange in the Cu atom is found to provide a strong (~ eV) electron pairing interaction. A Bardeen–Cooper–Schrieffer approach can explain the main experimental observations and predict the correct dx2-y2 symmetry of the gap.

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