The thermolysis of18O labelled t-butyl NN-dimethyl carbamate and its possible bearing on the course of thermal β-elimination reaction mechanisms

1972 ◽  
pp. 552-553 ◽  
Author(s):  
Harold Kwart ◽  
Joel Slutsky
Keyword(s):  
Reaction Mechanisms ◽  
Elimination Reaction

Low Temperature Synthesis of Plasma Teos SiO2

1996 ◽  
Vol 446 ◽  
Author(s):  
T. Itani ◽  
S. Fukuyama
Keyword(s):  
Reaction Mechanisms ◽  
Plasma Reactor ◽  
Substrate Surface ◽  
Condensation Reaction ◽  
Excitation Frequency ◽  
Elimination Reaction ◽  
Film Properties ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Precursor Molecules

AbstractIn this study, we investigated the deposition temperature's affect on TEOS based Si02 properties and reaction mechanisms while changing the excitation frequency. We used a parallel-plate plasma reactor, and either 100 kHz or 13.56 MHz radio frequency to generate plasma. We found that 100 kHz plasma promotes SiO formation and improves the film properties at low deposition temperatures. We assume this to be due to the supplement of higher energy ions to the substrate surface in 100 kHz plasma. This in turn promotes the elimination reaction (condensation reaction) of OH that links to Si atoms as a terminator of surface SiO networks or precursor molecules.

scholarly journals Protoenzymes: the case of hyperbranched polyesters

2017 ◽  
Vol 375 (2109) ◽  
pp. 20160357 ◽  
Author(s):  
Irena Mamajanov ◽  
George D. Cody
Keyword(s):  
Reaction Mechanisms ◽  
Metabolic Pathways ◽  
Hyperbranched Polymers ◽  
Specific Substrate ◽  
Complex Structures ◽  
Elimination Reaction ◽  
Globular Structure ◽  
Hyperbranched Polyesters ◽  
Methylsuccinic Acid ◽  
Polymeric Structures

Enzymes are biopolymeric complexes that catalyse biochemical reactions and shape metabolic pathways. Enzymes usually work with small molecule cofactors that actively participate in reaction mechanisms and complex, usually globular, polymeric structures capable of specific substrate binding, encapsulation and orientation. Moreover, the globular structures of enzymes possess cavities with modulated microenvironments, facilitating the progression of reaction(s). The globular structure is ensured by long folded protein or RNA strands. Synthesis of such elaborate complexes has proven difficult under prebiotically plausible conditions. We explore here that catalysis may have been performed by alternative polymeric structures, namely hyperbranched polymers. Hyperbranched polymers are relatively complex structures that can be synthesized under prebiotically plausible conditions; their globular structure is ensured by virtue of their architecture rather than folding. In this study, we probe the ability of tertiary amine-bearing hyperbranched polyesters to form hydrophobic pockets as a reaction-promoting medium for the Kemp elimination reaction. Our results show that polyesters formed upon reaction between glycerol, triethanolamine and organic acid containing hydrophobic groups, i.e. adipic and methylsuccinic acid, are capable of increasing the rate of Kemp elimination by a factor of up to 3 over monomeric triethanolamine. This article is part of the themed issue ‘Reconceptualizing the origins of life’.

Kinetic correlations for H2 addition and elimination reaction mechanisms during silicon hydride pyrolysis

2010 ◽  
Vol 12 (39) ◽  
pp. 12676 ◽  
Author(s):  
Andrew J. Adamczyk ◽  
Marie-Françoise Reyniers ◽  
Guy B. Marin ◽  
Linda J. Broadbelt
Keyword(s):  
Reaction Mechanisms ◽  
Elimination Reaction ◽  
Silicon Hydride ◽  
H2 Addition

Evidence of a Borderline Region between E1cb and E2 Elimination Reaction Mechanisms:  A Combined Experimental and Theoretical Study of Systems Activated by the Pyridine Ring

2005 ◽  
Vol 127 (43) ◽  
pp. 15151-15160 ◽  
Author(s):  
Sergio Alunni ◽  
Filippo De Angelis ◽  
Laura Ottavi ◽  
Magdalini Papavasileiou ◽  
Francesco Tarantelli
Keyword(s):  
Reaction Mechanisms ◽  
Pyridine Ring ◽  
Theoretical Study ◽  
Elimination Reaction

Analyzing reactions of single mechanoenzyme molecules by light microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 426-427
Author(s):  
Jeff Gelles
Keyword(s):  
Image Processing ◽  
Reaction Mechanisms ◽  
Transient State ◽  
Nanometer Scale ◽  
Reaction Intermediates ◽  
Enzyme Molecule ◽  
Directed Movement ◽  
Enzyme Molecules ◽  
Individual Enzyme ◽  
Single Reaction

Mechanoenzymes are enzymes which use a chemical reaction to power directed movement along biological polymer. Such enzymes include the cytoskeletal motors (e.g., myosins, dyneins, and kinesins) as well as nucleic acid polymerases and helicases. A single catalytic turnover of a mechanoenzyme moves the enzyme molecule along the polymer a distance on the order of 10−9 m We have developed light microscope and digital image processing methods to detect and measure nanometer-scale motions driven by single mechanoenzyme molecules. These techniques enable one to monitor the occurrence of single reaction steps and to measure the lifetimes of reaction intermediates in individual enzyme molecules. This information can be used to elucidate reaction mechanisms and determine microscopic rate constants. Such an approach circumvents difficulties encountered in the use of traditional transient-state kinetics techniques to examine mechanoenzyme reaction mechanisms.

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