Hydrolysis of esters of sulfur-containing acids in oxygen-18 enriched media

1968 ◽  
Vol 90 (17) ◽  
pp. 4626-4628 ◽  
Author(s):  
E. T. Kaiser ◽  
O. R. Zaborsky
Keyword(s):  
Hydrolysis Of Esters ◽  
Hydrolysis Of ◽  
Sulfur Containing

The Effects of Amines on the Esterase Activities of Thrombin and Thrombokinase and on Several Clotting Tests

1974 ◽  
Vol 31 (02) ◽  
pp. 309-318
Author(s):  
Phyllis S Roberts ◽  
Raphael M Ottenbrite ◽  
Patricia B Fleming ◽  
James Wigand
Keyword(s):  
Choline Chloride ◽  
Polymerization Process ◽  
Ammonium Bromide ◽  
Bovine Thrombin ◽  
One Stage ◽  
Human Proteins ◽  
Rate Of Hydrolysis ◽  
The One ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

Summary1. Choline chloride, 0.1 M (in 0.25 M Tris. HCl buffer, pH 7.4 or 8.0, 37°), doubles the rate of hydrolysis of TAME by bovine thrombokinase but has no effect on the hydrolysis of this ester by either human or bovine thrombin. Only when 1.0 M or more choline chloride is present is the hydrolysis of BAME by thrombokinase or thrombin weakly inhibited. Evidence is presented that shows that these effects are due to the quaternary amine group.2. Tetramethyl ammonium bromide or chloride has about the same effects on the hydrolysis of esters by these enzymes as does choline chloride but tetra-ethyl, -n.propyl and -n.butyl ammonium bromides (0.1 M) are stronger accelerators of the thrombokinase-TAME reaction and they also accelerate, but to a lesser degree, the thrombin-TAME reaction. In addition, they inhibit the hydrolysis of BAME by both enzymes. Their effects on these reactions, however, do not follow any regular order. The tetraethyl compound is the strongest accelerator of the thrombokinase-TAME reaction but the tetra-ethyl and -butyl compounds are the strongest accelerators of the thrombin-TAME reaction. The ethyl and propyl compounds are the best (although weak) inhibitors of the thrombokinase-BAME and the propyl compound of the thrombin-BAME reactions.3. Tetra-methyl, -ethyl, -n.propyl and -n.butyl ammonium bromides (0.01 M) inhibit the clotting of fibrinogen by thrombin (bovine and human proteins) at pH 7.4, imidazole or pH 6.1, phosphate buffers and they also inhibit, but to a lesser degree, a modified one-stage prothrombin test. In all cases the inhibition increases regularly as the size of the alkyl group increases from methyl to butyl. Only the ethyl com pound (0.025 M but not 0.01 M), however, significantly inhibits the polymerization of bovine fibrin monomers. It was concluded that inhibition of the fibrinogen-thrombin and the one-stage tests by the quaternary amines is not due to any effect of the com pounds on the polymerization process but probably due to inhibition of thrombin’s action on fibrinogen by the quaternary amines.

295. Ion-exchange resins as catalysts in the hydrolysis of esters

1952 ◽  
pp. 1607 ◽  
Author(s):  
C. W. Davies ◽  
G. Garrod Thomas
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Resins ◽  
Exchange Resins ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

scholarly journals On the Effect of Bile Upon the Hydrolysis of Esters by Pancreatic Juice

1907 ◽  
Vol 2 (5) ◽  
pp. 415-425 ◽  
Author(s):  
A.S. Loevenhart ◽  
C.G. Souder
Keyword(s):  
Pancreatic Juice ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

scholarly journals The α-Chymotrypsin-catalyzed Hydrolysis of Esters of α-Amino Acids

1972 ◽  
Vol 247 (18) ◽  
pp. 5746-5752
Author(s):  
Ferenc J. Kézdy ◽  
Satya P. Jindal ◽  
Myron L. Bender
Keyword(s):  
Amino Acids ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

Water-tolerant solid acid catalysis of Cs2.5H0.5PW12O40 for hydrolysis of esters in the presence of excess water

1997 ◽  
Vol 165 (1-2) ◽  
pp. 227-240 ◽  
Author(s):  
Mutsuko Kimura ◽  
Teruyuki Nakato ◽  
Toshio Okuhara
Keyword(s):  
Acid Catalysis ◽  
Solid Acid ◽  
Solid Acid Catalysis ◽  
Excess Water ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

scholarly journals Studies on the sulfur-containing chelating agents. XLVI. Hydrolysis of thio-.BETA.-diketones and related amides in acetonitrile-water mixture.

1977 ◽  
Vol 25 (1) ◽  
pp. 158-162 ◽  
Author(s):  
SHIGENORI HARADA ◽  
MINORU SAWADA ◽  
MASAHIKO CHIKUMA ◽  
AKIRA YOKOYAMA ◽  
HISASHI TANAKA
Keyword(s):  
Chelating Agents ◽  
Water Mixture ◽  
Hydrolysis Of ◽  
Sulfur Containing

Bi(III) as New Catalyst for the Selective Hydrolysis of Esters

1997 ◽  
Vol 38 (17) ◽  
pp. 2981-2984 ◽  
Author(s):  
Véronique Le Boisselier ◽  
Michèle Postel ◽  
Elisabet Duñach
Keyword(s):  
Selective Hydrolysis ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

Accelerated hydrolysis of esters catalyzed by receptors, II. Degradation of RNA by polyvinylpyrrolidone

1999 ◽  
Vol 66 (1) ◽  
pp. 121-126
Author(s):  
Sung-Sik You ◽  
Hyeong-Won Ryu ◽  
Young Cho ◽  
Dae-Young Kim ◽  
Thong-Sung Ko
Keyword(s):  
Hydrolysis Of Esters ◽  
Hydrolysis Of

Kinetic Study of Hydrolysis of Benzoates. Part XXV. Ortho Substituent Effect in Alkaline Hydrolysis of Phenyl Esters of Substituted Benzoic Acids in Water

2006 ◽  
Vol 71 (1) ◽  
pp. 107-128 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Vahur Mäemets ◽  
Ilmar Koppel
Keyword(s):  
Acid Hydrolysis ◽  
Alkaline Hydrolysis ◽  
Substituent Effect ◽  
Ethyl Esters ◽  
Benzoic Acids ◽  
Neat Water ◽  
Substituted Benzoic Acids ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

The second-order rate constants k2 for alkaline hydrolysis of phenyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2C6H5 (X = H, 3-Cl, 3-NO2, 3-CH3, 4-NO2, 4-Cl, 4-F, 4-CH3, 4-OCH3, 4-NH2, 2-NO2, 2-CN, 2-F, 2-Cl, 2-Br, 2-I, 2-CH3, 2-OCH3, 2-CF3, 2-NH2), and of substituted phenyl esters of benzoic acid, C6H5CO2C6H4-X (X = 2-I, 2-CF3, 2-C(CH3)3, 4-Cl, 4-CH3, 4-OCH3, 4-NH2), have been measured spectrophotometrically in water at 25 °C. The substituent effect in alkaline hydrolysis of phenyl esters of para-substituted benzoic acids, similar to that for ethyl esters of para-substituted benzoic acids, was found to be precisely described by the Hammett relationship (ρ = 1.7 in water). The log k value for alkaline hydrolysis of phenyl and ethyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2R, was nicely correlated with log km,p,ortho = log ko + (ρ)m,pσ + (ρI)orthoσI + (ρ°R)orthoσ°R + δorthoEsB where σ, σI, σ°R are the Hammett polar, Taft inductive and Taft resonance (σ°R = σ° - σI) substituent constants, respectively. EsB is the steric scale for ortho substituents calculated on the basis of the log k values for the acid hydrolysis of ortho- substituted phenyl benzoates in water owing to the ortho substituent in the phenyl of phenyl benzoates. In water, the main factors responsible for changes in the ortho substituent effect in alkaline hydrolysis of phenyl and ethyl esters of ortho-substituted benzoic acids, X-C6H4CO2R, were found to be the inductive and steric factors while the role of the resonance term was negligible ((ρ°R)ortho ca. 0.3). In alkaline hydrolysis of substituted benzoates in neat water, the ortho inductive effect appeared to be 1.5 times and steric influence 2.7 times higher than the corresponding influences from the ortho position in the phenyl of phenyl benzoates. The contributions of the steric effects in alkaline hydrolysis of esters of ortho-substituted benzoic acids was found to be approximately the same as in acid hydrolysis of esters of ortho-substituted benzoic and acid esterification of ortho-substituted benzoic acids.

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