Hydrolysis of acetylthiocholine iodide and reactivation of phoxim-inhibited acetylcholinesterase by pralidoxime chloride, obidoxime chloride and trimedoxime

2007 ◽  
Vol 81 (11) ◽  
pp. 785-792 ◽  
Author(s):  
Yi Hui Zhang ◽  
Tadashi Miyata ◽  
Zhu Jian Wu ◽  
Gang Wu ◽  
Lian Hui Xie
Keyword(s):  
Acetylthiocholine Iodide ◽  
Pralidoxime Chloride ◽  
Hydrolysis Of ◽  
Obidoxime Chloride

Study on Immobilization Methods of Acetylcholinesterase

2008 ◽  
Vol 4 (8) ◽  
Author(s):  
Xia Sun ◽  
Xiangyou Wang ◽  
Zhe Liu
Keyword(s):  
Sol Gel ◽  
Organophosphorus Pesticide ◽  
Cross Linking ◽  
Gel Method ◽  
Sol Gel Method ◽  
Oxidation Current ◽  
Acetylthiocholine Iodide ◽  
Chitosan Membranes ◽  
Hydrolysis Of ◽  
Made In

In this paper, two acetylcholinesterase (AChE) immobilization methods on the surface of a glassy carbon electrode (GCE) were compared. AChE-employed homogenate from chicken brain was home-made in the laboratory. The immobilization methods employed a cross-linking method with glutaraldehyde as a cross-linking agent, bovine serum albumin (BSA) as a protectant, and sol-gel method with tetraethoxysilane (TEOS). AChE was immobilized on chitosan membranes by these two immobilization methods. Then the enzyme membrane was fixed on the surface of GCE to prepare an AChE-GCE amperometric biosensor for the detection of organophosphorus pesticide. Measuring the activity of immobilization AChE by the oxidation current of thiocholine (TCh), produced by hydrolysis of the acetylthiocholine iodide (ATChI) substrate, the results showed that the activity of AChE-employed sol-gel method with TEOS was higher than the cross-linking method with glutaraldehyde. Biosensor sensitivity and reproducibility were statistically evaluated for the different immobilization methods and the most suitable immobilization procedure was selected.

Kinetics of acetylcholinesterase immobilized on polyethylene tubing

1979 ◽  
Vol 57 (10) ◽  
pp. 1200-1203 ◽  
Author(s):  
T. T. Ngo ◽  
K. J. Laidler ◽  
C. F. Yam
Keyword(s):  
Diffusion Control ◽  
Initial Oxidation ◽  
Diffusion Controlled ◽  
Kinetic Tests ◽  
Acetylthiocholine Iodide ◽  
Carboxylic Groups ◽  
Michaelis Constants ◽  
Polyethylene Tubing ◽  
Kinetics Of ◽  
Hydrolysis Of

Acetylcholinesterase was covalently attached to the inner surface of polyethylene tubing. Initial oxidation generated surface carboxylic groups which, on reaction with thionyl chloride, produced acid chloride groups; these were caused to react with excess ethylenediamine. The amine groups on the surface were linked to glutaraldehyde, and acetylcholinesterase was then attached to the surface. Various kinetic tests showed the catalysis of the hydrolysis of acetylthiocholine iodide to be diffusion controlled. The apparent Michaelis constants were strongly dependent on flow rate and were much larger than the value for the free enzyme. Rate measurements over the temperature range 6–42 °C showed changes in activation energies consistent with diffusion control.

Fine Structural Localization of Acyltransferases Involved in Lipid Synthesis in Intestinal Mucosa.

1970 ◽  
Vol 28 ◽  
pp. 54-55
Author(s):  
R. J. Barrnett ◽  
J. A. Higgins
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Lipid Synthesis ◽  
Mucosal Cell ◽  
Structural Localization ◽  
Morphological Studies ◽  
Mucosal Cells ◽  
Initial Appearance ◽  
Sh Group ◽  
Hydrolysis Of ◽  
Intestinal Mucosal Cells

The main products of intestinal hydrolysis of dietary triglycerides are free fatty acids and monoglycerides. These form micelles from which the lipids are absorbed across the mucosal cell brush border. Biochemical studies have indicated that intestinal mucosal cells possess a triglyceride synthesising system, which uses monoglyceride directly as an acylacceptor as well as the system found in other tissues in which alphaglycerophosphate is the acylacceptor. The former pathway is used preferentially for the resynthesis of triglyceride from absorbed lipid, while the latter is used mainly for phospholipid synthesis. Both lipids are incorporated into chylomicrons. Morphological studies have shown that during fat absorption there is an initial appearance of fat droplets within the cisternae of the smooth endoplasmic reticulum and that these subsequently accumulate in the golgi elements from which they are released at the lateral borders of the cell as chylomicrons.We have recently developed several methods for the fine structural localization of acyltransferases dependent on the precipitation, in an electron dense form, of CoA released during the transfer of the acyl group to an acceptor, and have now applied these methods to a study of the fine structural localization of the enzymes involved in chylomicron lipid biosynthesis. These methods are based on the reduction of ferricyanide ions by the free SH group of CoA.

Lattice imaging and pore structure of β ferric oxyhydroxide

1978 ◽  
Vol 36 (1) ◽  
pp. 264-265
Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bulk Material ◽  
Model Structure ◽  
Bulk Crystals ◽  
Lattice Imaging ◽  
Thin Sections ◽  
Ferric Oxyhydroxide ◽  
Resolution Electron ◽  
Hydrolysis Of

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.

Elucidating cyclic AMP signaling in subcellular domains with optogenetic tools and fluorescent biosensors

2019 ◽  
Vol 47 (6) ◽  
pp. 1733-1747 ◽  
Author(s):  
Christina Klausen ◽  
Fabian Kaiser ◽  
Birthe Stüven ◽  
Jan N. Hansen ◽  
Dagmar Wachten
Keyword(s):  
Cyclic Amp ◽  
Adenosine Monophosphate ◽  
Adenylyl Cyclases ◽  
Temporal Precision ◽  
Fluorescent Biosensors ◽  
Subcellular Domains ◽  
Spatio Temporal ◽  
Hydrolysis Of ◽  
Shed Light ◽  
Cyclic Amp Signaling

The second messenger 3′,5′-cyclic nucleoside adenosine monophosphate (cAMP) plays a key role in signal transduction across prokaryotes and eukaryotes. Cyclic AMP signaling is compartmentalized into microdomains to fulfil specific functions. To define the function of cAMP within these microdomains, signaling needs to be analyzed with spatio-temporal precision. To this end, optogenetic approaches and genetically encoded fluorescent biosensors are particularly well suited. Synthesis and hydrolysis of cAMP can be directly manipulated by photoactivated adenylyl cyclases (PACs) and light-regulated phosphodiesterases (PDEs), respectively. In addition, many biosensors have been designed to spatially and temporarily resolve cAMP dynamics in the cell. This review provides an overview about optogenetic tools and biosensors to shed light on the subcellular organization of cAMP signaling.

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