Enzymes that catalyse SN2 reaction mechanisms

2010 ◽  
Vol 27 (6) ◽  
pp. 900 ◽  
Author(s):  
David O'Hagan ◽  
Jason W. Schmidberger
Keyword(s):  
Reaction Mechanisms ◽  
Sn2 Reaction

ChemInform Abstract: Enzymes that Catalyze SN2 Reaction Mechanisms

ChemInform ◽  
2010 ◽  
Vol 41 (37) ◽  
pp. no-no
Author(s):  
David O'Hagan ◽  
Jason W. Schmidberger
Keyword(s):  
Reaction Mechanisms ◽  
Sn2 Reaction

Newly proposed proton-abstraction roundabout with backside attack mechanism for the SN2 reaction at the nitrogen center in F− + NH2Cl

2018 ◽  
Vol 20 (17) ◽  
pp. 12106-12111 ◽  
Author(s):  
Yongfang Li ◽  
Dunyou Wang
Keyword(s):  
Reaction Mechanisms ◽  
Proton Abstraction ◽  
Sn2 Reaction ◽  
Nitrogen Center

Two novel reaction mechanisms are revealed for the SN2 reaction at the nitrogen center in the F− + NH2Cl 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.

X-Ray Microanalysis of Nickel and Cobalt Intensified Peroxidase- Antiperoxidase For Verification of Reaction Sites

1985 ◽  
Vol 43 ◽  
pp. 468-469
Author(s):  
A. Angel ◽  
K. Miller ◽  
V. Seybold ◽  
R. Kriebel
Keyword(s):  
Reaction Mechanisms ◽  
Visual Discrimination ◽  
Osmium Tetroxide ◽  
Ultrastructural Level ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
X Ray ◽  
Insoluble Polymer ◽  
Cytochemical Reaction

Localization of specific substances at the ultrastructural level is dependent on the introduction of chemicals which will complex and impart an electron density at specific reaction sites. Peroxidase-antiperoxidase(PAP) methods have been successfully applied at the electron microscopic level. The PAP complex is localized by addition of its substrate, hydrogen peroxide and an electron donor, usually diaminobenzidine(DAB). On oxidation, DAB forms an insoluble polymer which is able to chelate with osmium tetroxide becoming electron dense. Since verification of reactivity is visual, discrimination of reaction product from osmiophillic structures may be difficult. Recently, x-ray microanalysis has been applied to examine cytochemical reaction precipitates, their distribution in tissues, and to study cytochemical reaction mechanisms. For example, immunoreactive sites labelled with gold have been ascertained by means of x-ray microanalysis.

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