scholarly journals Multiple Reaction Products from the Hydrolysis of Chiral and Prochiral Organophosphate Substrates by the Phosphotriesterase from Sphingobium sp. TCM1

Biochemistry ◽  
2018 ◽  
Vol 57 (12) ◽  
pp. 1842-1846 ◽  
Author(s):  
Andrew N. Bigley ◽  
Tamari Narindoshvili ◽  
Dao Feng Xiang ◽  
Frank M. Raushel
Keyword(s):  
Reaction Products ◽  
Hydrolysis Of

A Fluorescence Polarization Assay for Cyclic Nucleotide Phosphodiesterases

2002 ◽  
Vol 7 (3) ◽  
pp. 215-222 ◽  
Author(s):  
Wei Huang ◽  
Yan Zhang ◽  
J. Richard Sportsman
Keyword(s):  
Cyclic Nucleotide ◽  
Fluorescence Polarization ◽  
Drug Targets ◽  
Second Messengers ◽  
Reaction Products ◽  
Cyclic Nucleotide Phosphodiesterases ◽  
Extracellular Signals ◽  
Fluorescence Polarization Assay ◽  
Hydrolysis Of ◽  
Nucleotide Phosphodiesterases

Cyclic nucleotide phosphodiesterases (PDEs) catalyze the hydrolysis of the 3′-ester bond of cyclic AMP (cAMP) and cyclic GMP (cGMP), important second messengers in the transduction of a variety of extracellular signals. There is growing interest in the study of PDEs as drug targets for novel therapeutics. We describe the development of a homogeneous fluorescence polarization assay for PDEs based on the strong binding of PDE reaction products (i.e., AMP or GMP) onto modified nanoparticles through interactions with immobilized trivalent metal cations. This assay technology (IMAP) is applicable to both cAMP- and cGMP-specific PDEs. Results of the assay in 384- and 1536-well microplates are presented.

Darstellung von o-Phenylen-bis(dibromphosphan) — Reaktionsprodukte von o-Phenylen-bis(dichlorphosphan) / Synthesis of o-Phenylene-bis(dibromophosphane) — Reaction Products of o-Phenylene-bis(dichlorophosphane)

1984 ◽  
Vol 39 (12) ◽  
pp. 1706-1710 ◽  
Author(s):  
H.-J. Wörz ◽  
E. Quien ◽  
H. P. Latscha
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Bromide ◽  
Equimolar Amount ◽  
Reaction Products ◽  
Large Excess ◽  
Cyclic Anhydride ◽  
Complete Hydrolysis ◽  
Hydrolysis Of

o-Phenylene-bis(dibromophosphane) (1) is prepared by reaction of P ,P,P′,P′-tetrakis(dim ethylamino)-o-phenylenediphosphane with hydrogen bromide in ether. The reaction of o-phenylene- bis(dichlorophosphane) (2) with CH3OH in ether yields o-phenylene-bis(phosphonousacid- dimethylester) (3). The Michaelis-Arbuzov conversion of 3, either by heat or by catalytic amounts of CH3I in toluene, yields ophenylene-bis(methylphosphinic-acid-methylester) (4). The reduction of 2 must be carried out with a large excess of LiAlH4 (1:4) in ether to give o-phenylenediphosphane (5). The cyclic anhydride (6) of P.P′-dichloro-o-phenylenediphosphonous acid is formed when 2 is hydrolyzed in ether with an equimolar amount of water. Complete hydrolysis of 2 with an excess of water gives o-phenylenediphosphonous acid (7). With hydrogen peroxide o-phenylenediphosphonic acid (8) can be isolated.

The acid-catalysed hydrolysis of α-methylallyl acetate in aqueous solution

1968 ◽  
Vol 21 (7) ◽  
pp. 1727
Author(s):  
RA Fredlein ◽  
I Lauder
Keyword(s):  
Aqueous Solution ◽  
Reaction Products ◽  
Arrhenius Parameters ◽  
Crotyl Alcohol ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Tracer Experiments

The kinetics of the acid-catalysed hydrolysis of a-methylallyl acetate in aqueous solution have been studied over the range 30-100�. Oxygen-18 tracer experiments reveal the mechanism to be solely Aac2 and the Arrhenius parameters are consistent with this conclusion. Crotyl alcohol is observed in the reaction products. The formation of rearranged alcohol is explained by allylic isomerization of the α-methylallyl alcohol produced by the hydrolysis.

Hydrolysis of friedel-crafts reaction products at different temperatures

2007 ◽  
Vol 30 (1) ◽  
pp. 642-647
Author(s):  
D. Ian Barnes ◽  
J. Gordon Robinson ◽  
George Marr
Keyword(s):  
Reaction Products ◽  
Different Temperatures ◽  
Hydrolysis Of

scholarly journals Rat Serum Carboxylesterase Partly Hydrolyses Gamma-Butyrobetaine Esters

2009 ◽  
Vol 60 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Lida Bagdonienė ◽  
Danutė Labeikytė ◽  
Ivars Kalviņš ◽  
Veronika Borutinskaitė ◽  
Aleksandrs Prokofjevs ◽  
...  
Keyword(s):  
Blood Serum ◽  
Esterase Activity ◽  
Colorimetric Determination ◽  
Reaction Products ◽  
Rat Serum ◽  
Rat Blood ◽  
Optical Absorbance ◽  
Hydrolysis Of ◽  
Related Compounds

Rat Serum Carboxylesterase Partly Hydrolyses Gamma-Butyrobetaine EstersAlthough described some time ago, gamma-butyrobetaine esters and related compounds have not gained much attention from researchers, and their physiological function remains obscure. Formerly we detected GBB-esterase enzymatic activity in rat blood serum using phenylated gamma-butyrobetaine as an artificial substrate of the enzyme and HPLC. The aim of the present work was to develop an assay that would enable spectrophotometric or colorimetric determination of the reaction products of GBB-esterase activity and to reveal individual proteins performing GBB-esterase activity in rat blood serum. For this purpose gamma-butyrobetaine 1-naphthyl ester was synthesised. Hydrolysis of this ester releases 1-naphthol, which increases the optical absorbance at 322 nm. We have shown that the enzymatic hydrolysis of GBB 1-naphthyl ester to 1-naphthol in rat blood serum is due to GBB-esterase activity. An attempt was done to purify the enzyme from rat blood serum. By combining DEAE Sepharose at pH 4.2 and affinity chromatography with procainamide we achieved a 68-fold enrichment of GBB-esterase activity in our preparations. Separation of fraction proteins in 2D protein electrophoresis with following mass-spectrometry indicated that GBB esterase activity in rat blood serum is performed in part by carboxylesterase.

scholarly journals Reaction mechanism of chitosanase from Streptomyces sp. N174

1995 ◽  
Vol 311 (2) ◽  
pp. 377-383 ◽  
Author(s):  
T Fukamizo ◽  
Y Honda ◽  
S Goto ◽  
I Boucher ◽  
R Brzezinski
Keyword(s):  
Nmr Spectra ◽  
Time Course ◽  
Product Distribution ◽  
Time Dependent ◽  
Reaction Products ◽  
Streptomyces Sp ◽  
Substrate Degradation ◽  
Time Courses ◽  
Binding Cleft ◽  
Hydrolysis Of

Chitosanase was produced by the strain of Streptomyces lividans TK24 bearing the csn gene from Streptomyces sp. N174, and purified by S-Sepharose and Bio-Gel A column chromatography. Partially (25-35%) N-acetylated chitosan was digested by the purified chitosanase, and structures of the products were analysed by NMR spectroscopy. The chitosanase produced heterooligosaccharides consisting of D-GlcN and GlcNAc in addition to glucosamine oligosaccharides [(GlcN)n, n = 1, 2 and 3]. The reducing- and non-reducing-end residues of the heterooligosaccharide products were GlcNAc and GlcN respectively, indicating that the chitosanase can split the GlcNAc-GlcN linkage in addition to that of GlcN-GlcN. Time-dependent 1H-NMR spectra showing hydrolysis of (GlcN)6 by the chitosanase were obtained in order to determine the anomeric form of the reaction products. The chitosanase was found to produce only the alpha-form; therefore it is an inverting enzyme. Separation and quantification of (GlcN)n was achieved by HPLC, and the time course of the reaction catalysed by the chitosanase was studied using (GlcN)n (n = 4, 5 and 6) as the substrate. The chitosanase hydrolysed (GlcN)6 in an endo-splitting manner producing (GlcN)2, (GlcN)3 and (GlcN)4, and did not catalyse transglycosylation. Product distribution was (GlcN)3 >> (GlcN)2 > (GlcN)4. Cleavage to (GlcN)3 + (GlcN)3 predominated over that to (GlcN)2 + (GlcN)4. Time courses showed a decrease in rate of substrate degradation from (GlcN)6 to (GlcN)5 to (GlcN)4. It is most likely that the substrate-binding cleft of the chitosanase can accommodate at least six GlcN residues, and that the cleavage point is located at the midpoint of the binding cleft.

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