542. The hydrolysis of carboxylic anhydrides. Part III. Reactions in initially neutral solution

1963 ◽  
pp. 2918 ◽  
Author(s):  
C. A. Bunton ◽  
N. A. Fuller ◽  
S. G. Perry ◽  
V. J. Shiner
Keyword(s):  
Neutral Solution ◽  
Hydrolysis Of

Micellar catalysis of organic reactions. Part 33. Amide hydrolysis in neutral solution in the presence of a copper-containing micelle

1993 ◽  
Vol 71 (5) ◽  
pp. 670-673 ◽  
Author(s):  
Trevor J. Broxton ◽  
Robin A. Coa
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Cupric Chloride ◽  
Buffer Concentration ◽  
Neutral Solution ◽  
Hydroxide Ion ◽  
Amide Hydrolysis ◽  
Mechanism Of Reaction ◽  
Rate Of Reaction ◽  
Hydrolysis Of ◽  
Micelle Surface

The hydrolysis of 5-nitro-2-(trifluoroacetylamino)benzoic acid (1) has been studied at pH 7 in water and in the presence of micelles of cetyltrimethylammonium bromide (ctab) and of copper-containing micelles formed from the reaction of N,N,N′-trimethyl-N′-hexadecylethylenediamine and cupric chloride. It has been found that the hydrolysis of 1 is inhibited by micelles of ctab but strongly catalysed by the copper-containing micelle at this pH. At a higher pH where the hydroxide ion reaction becomes important the reaction is catalysed by micelles of ctab as well, but the catalysis is stronger by the copper-containing micelle. The effect of added sodium chloride on the rate of reaction is shown to be larger for reaction in the presence of ctab than for reaction in the presence of the copper micelles. Also reported are the effects of the buffer concentration on the rate of reaction at various pH for both micelles. It is concluded that the mechanism of reaction in the copper-containing micelle involves a metal-bound hydroxyl rather than a free hydroxide ion loosely associated with the cationic micelle surface. It is interesting that the catalysis of this reaction by the copper-containing micelle is large enough to allow amide hydrolysis at a reasonable rate at neutral pH at ambient temperature.

scholarly journals The reaction of penicillin with proteins

1975 ◽  
Vol 149 (2) ◽  
pp. 357-364 ◽  
Author(s):  
P H Corran ◽  
S G Waley
Keyword(s):  
Egg White ◽  
Amino Group ◽  
Neutral Solution ◽  
Egg White Lysozyme ◽  
Hen’S Egg ◽  
N Terminus ◽  
High Concentrations ◽  
A Chain ◽  
A Site ◽  
Hydrolysis Of

The mode of reaction of benzylpenicillin with two proteins was studied, with particular reference to the allergenicity of penicillin. These reactions, with pig insulin, and with hen's-egg-white lysozyme, were carried out in neutral solution at 37°C. High concentrations of penicillin are needed to label the proteins, owing to concurrent hydrolysis of penicillin. Evidence has been obtained that the penicillin-reactive sites on the insulin molecule are the α-amino group at the N-terminus of the A chain and the ε-amino group of the lysine residue; whereas a site of reaction with lysozyme appears to be the ε-amino group of lysine-116.

Hydrolysis of 2-aminopurine deoxyribonucleoside in neutral solution

1988 ◽  
Vol 53 (14) ◽  
pp. 3241-3246 ◽  
Author(s):  
Peter C. Ratsep ◽  
Reynaldo C. Pless
Keyword(s):  
Neutral Solution ◽  
Hydrolysis Of

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.

Sign in / Sign up

Export Citation Format

Share Document