Enzymatic reaction in water-in-oil microemulsions. Part 2.—Rate of hydrolysis of a hydrophobic substrate, 2-naphthyl acetate

1994 ◽  
Vol 90 (7) ◽  
pp. 979-986 ◽  
Author(s):  
Yoshikazu Miyake ◽  
Takuya Owari ◽  
Fumio Ishiga ◽  
Masaaki Teramoto
Keyword(s):  
Enzymatic Reaction ◽  
Hydrophobic Substrate ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Reaction In Water ◽  
Naphthyl Acetate

HYDROLYSIS OF GLYCEROLPHOSPHATIDES BY PLASTID PHOSPHATIDASE C

1956 ◽  
Vol 34 (5) ◽  
pp. 967-980 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Ethyl Ether ◽  
Phosphatidyl Choline ◽  
Phosphatidyl Ethanolamine ◽  
Enzymatic Reaction ◽  
Phosphatidyl Serine ◽  
Ph Optimum ◽  
Soybean Phosphatide ◽  
Optimum Ph ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Studies of the influence of structural variation in the glycerolphosphatide molecule on the hydrolysis of this class of compounds by plastid phosphatidase C showed that the presence of both fatty acid ester groups is necessary for enzymatic reaction; that release of nitrogenous bases occurred, in the presence of ethyl ether, from phosphatidyl cholines, phosphatidyl ethanolamine, and phosphatidyl serine; and that a phosphatidyl choline was hydrolyzed more rapidly than the corresponding phosphatidyl ethanolamine or phosphatidyl serine. The rate of hydrolysis of phosphatidyl choline was influenced greatly by the chain length and degree of unsaturation of the fatty acids. The corresponding phosphatidic acid formed in the hydrolysis of (dipalmitoyl)- or (dipalmitoleyl)-lecithin by carrot phosphatidase C was isolated. Studies on the hydrolysis of crude soybean phosphatide by phosphatidase C showed that both choline and ethanolamine were liberated in the absence of ethyl ether, at an optimum pH of 4.8; in the presence of ether, the rate of liberation of each base was increased, and the pH optimum was between 4.8 and 6. Soybean phosphatide probably contains a substance that stimulates the enzymatic hydrolysis.

HYDROLYSIS OF GLYCEROLPHOSPHATIDES BY PLASTID PHOSPHATIDASE C

1956 ◽  
Vol 34 (1) ◽  
pp. 967-980 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Ethyl Ether ◽  
Phosphatidyl Choline ◽  
Phosphatidyl Ethanolamine ◽  
Enzymatic Reaction ◽  
Phosphatidyl Serine ◽  
Ph Optimum ◽  
Soybean Phosphatide ◽  
Optimum Ph ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Studies of the influence of structural variation in the glycerolphosphatide molecule on the hydrolysis of this class of compounds by plastid phosphatidase C showed that the presence of both fatty acid ester groups is necessary for enzymatic reaction; that release of nitrogenous bases occurred, in the presence of ethyl ether, from phosphatidyl cholines, phosphatidyl ethanolamine, and phosphatidyl serine; and that a phosphatidyl choline was hydrolyzed more rapidly than the corresponding phosphatidyl ethanolamine or phosphatidyl serine. The rate of hydrolysis of phosphatidyl choline was influenced greatly by the chain length and degree of unsaturation of the fatty acids. The corresponding phosphatidic acid formed in the hydrolysis of (dipalmitoyl)- or (dipalmitoleyl)-lecithin by carrot phosphatidase C was isolated. Studies on the hydrolysis of crude soybean phosphatide by phosphatidase C showed that both choline and ethanolamine were liberated in the absence of ethyl ether, at an optimum pH of 4.8; in the presence of ether, the rate of liberation of each base was increased, and the pH optimum was between 4.8 and 6. Soybean phosphatide probably contains a substance that stimulates the enzymatic hydrolysis.

scholarly journals Genetic control of the hydrolysis of aromatic esters by sheep plasma A-esterase

1966 ◽  
Vol 7 (3) ◽  
pp. 373-382 ◽  
Author(s):  
R. M. Lee
Keyword(s):  
Esterase Activity ◽  
Phosphate Esters ◽  
Hydrolysis Rate ◽  
Aromatic Esters ◽  
Hydrolysis Rates ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Naphthyl Acetate ◽  
Genetic Marking ◽  
Genetic Hypothesis

1. The rate of hydrolysis by sheep plasma of some carboxylic and phosphate esters has been determined for a random flock, and for a flock previously selected for its ability to hydrolyse di-(2-chloroethyl) aryl phosphates.2. A discontinuous variation in hydrolysis rate was found with all substrates tested and, using combinations of substrates, six types of plasma could be distinguished, each type having a different pattern of esterase activity.3. The most useful substrates for distinguishing between phenotypes were 1-naphthyl acetate and 4-ethoxycarbonylcoumarin-7-yl acetate. Three rates of hydrolysis were possible for each of these esters, and the highest rate for one was invariably combined with the lowest rate for the other, although the converse did not apply.4. To explain these results, and those of Lee (1964), it has been postulated that the quantitative production of esterase hydrolysing 1-naphthyl acetate is governed by the presence of an allele, termed Esa, at a particular gene locus. Similarly, the production of esterase hydrolysing 4-ethoxycarbonylcoumarin-7-yl acetate is determined by allele Esb, and where neither substrate is attacked the presence of a third allele, Esc, is proposed.5. The hydrolysis rates of haloxon, 1-naphthyl butyrate and 4-nitrophenyl butyrate varied in the same way as that of 1-naphthyl acetate, whereas the hydrolysis of indophenyl acetate followed the same pattern as that of 4-ethoxycarbonylcoumarin-7-yl acetate. The variation in hydrolysis rate of Coroxon could be explained by assuming that Esa and Esb are equal in this respect.6. A mating experiment produced results which were in accordance with the genetic hypothesis, but were too few in number to provide confirmation.7. The genetic marking of six types of sheep is possible, utilizing the variation in plasma A-esterase activity.

REACTIONS OF ARYLSULPHONIC ESTERS: III. ON THE HYDROLYSIS OF METHYL p-METHYLBENZENESULPHONATE

1955 ◽  
Vol 33 (10) ◽  
pp. 1536-1543 ◽  
Author(s):  
R. E. Robertson
Keyword(s):  
Specific Heat ◽  
Temperature Dependence ◽  
Specific Solvation ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Reaction In Water

A study of the temperature dependence for the rate of hydrolysis of methyl p-methylbenzenesulphonate shows the specific heat of activation for this reaction in water to be 33.45 ± 3 cal./mole degree. A comparison with the corresponding term for other methyl compounds reveals differences apparently characteristic of the anionic portion of the molecule. These differences are discussed in terms of specific solvation.

Solvent reorganization for hydrolysis with hydrogen participation

1969 ◽  
Vol 47 (24) ◽  
pp. 4599-4605 ◽  
Author(s):  
Y. Inomoto ◽  
R. E. Robertson ◽  
G. Sarkis
Keyword(s):  
Acetic Acid ◽  
Isotope Effect ◽  
Activation Process ◽  
Solvent Isotope Effect ◽  
Butyl Bromide ◽  
Rate Of Hydrolysis ◽  
Solvent Isotope ◽  
Hydrolysis Of ◽  
Reaction In Water

A study of the rates of hydrolysis of 3-Me-2-butyl bromide and methanesulfonate in water leads to values of ΔCp≠ of −80 and −40 cal deg−1 mole−1, respectively. The product was about 85–95 % t-pentanol, the remainder being olefin. The value of ΔCp≠ for the solvolysis of the methanesulfonate in D2O was −44 cal deg−1 mole−1. The kinetic solvent isotope effect (k.s.i.e.) for the latter was unusually low (k.s.i.e. = 1.047 at 5 °C and 1.025 at 25 °C). Deuteration at C-3 led to a reduction in the rate of hydrolysis by a factor of about 2.25. This is consistent with an activation process involving "hydrogen participation" as previously reported by Winstein and Takahashi for solvolysis of the corresponding tosylate in acetic acid. In contrast to the latter work, the reaction in water appears to be uncomplicated.

EFFECTS OF OVARIAN STEROID HORMONES ON ESTERASES IN THE RAT ENDOMETRIUM

1975 ◽  
Vol 64 (3) ◽  
pp. 465-NP ◽  
Author(s):  
D. P. BOSHIER ◽  
JUNE M. KATZ
Keyword(s):  
Neutral Lipids ◽  
Mature Female ◽  
Female Rats ◽  
Luminal Epithelium ◽  
Tissue Extracts ◽  
Periodic Stimulation ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Naphthyl Acetate ◽  
Stimulation Of

SUMMARY A technique in which uterine luminal epithelium is separated from the remainder of the endometrium by rapidly vibrating everted uterine cornua in a 3·5 mm solution of EDTA has been developed. Examination of the hormonal sensitivities and physiological roles of the tissue components of the endometrium is thus facilitated. Biochemical and histochemical studies of epithelial, stromal and endometrial esterases have shown that the rate of hydrolysis of α-naphthyl acetate is significantly higher in epithelial and endometrial tissue extracts during pro-oestrus than at any other stage of the oestrous cycle. In ovariectomized animals, oestradiol-17β caused a 60% increase in the rate of esterase activity over that of control animals, whereas medroxyprogesterone acetate had no effect. These findings suggest that the variations in the levels of neutral lipids in the uterine luminal epithelium of non-pregnant mature female rats result from the periodic stimulation of the epithelial esterases by the cyclically increased levels of plasma oestrogens.

Substituent Effects on the Micelle-Catalysed and Uncatalysed Basic Hydrolysis of a Series of Substituted N-Methyl-p-toluanilides

1979 ◽  
Vol 32 (8) ◽  
pp. 1717 ◽  
Author(s):  
TJ Broxton ◽  
NW Duddy
Keyword(s):  
Substituent Effects ◽  
Cationic Micelles ◽  
Mechanism Of Reaction ◽  
Rate Of Reaction ◽  
Hammett Correlation ◽  
Rate Of Hydrolysis ◽  
Linear Plot ◽  
Basic Hydrolysis ◽  
Hydrolysis Of ◽  
Reaction In Water

The rate of hydrolysis of a series of substituted N-methyl-p-toluanilides has been measured in water and in the presence of cationic micelles [cetyltrimethylammonium bromide (ctab)]. A Hammett correlation of the rates of hydrolysis gave a curved Hammett plot for the reaction in water (k2,W) but a linear plot for the rate of reaction at optimal concentrations of ctab (k2,max) and for derived rate constants within the micelle (k2,m) These results are discussed in terms of the mechanism of reaction, and for two compounds a micelle-induced change of mechanism is indicated.

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.

The effect of polymeric and model imidazolium halides on the rate of hydrolysis of 4-acetoxy-3-nitrobenzoic acid

1985 ◽  
Vol 50 (4) ◽  
pp. 845-853 ◽  
Author(s):  
Miloslav Šorm ◽  
Miloslav Procházka ◽  
Jaroslav Kálal
Keyword(s):  
Catalyst Concentration ◽  
Low Molecular Weight ◽  
Imidazolium Chloride ◽  
First Order ◽  
Nitrobenzoic Acid ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Hydrolysis Of ◽  
Ethanol In Water ◽  
Direct Attack

The course of hydrolysis of an ester, 4-acetoxy-3-nitrobenzoic acid catalyzed with poly(1-methyl-3-allylimidazolium bromide) (IIa), poly[l-methyl-3-(2-propinyl)imidazolium chloride] (IIb) and poly[l-methyl-3-(2-methacryloyloxyethyl)imidazolium bromide] (IIc) in a 28.5% aqueous ethanol was investigated as a function of pH and compared with low-molecular weight models, viz., l-methyl-3-alkylimidazolium bromides (the alkyl group being methyl, propyl, and hexyl, resp). Polymers IIb, IIc possessed a higher activity at pH above 9, while the models were more active at a lower pH with a maximum at pH 7.67. The catalytic activity at the higher pH is attributed to an attack by the OH- group, while at the lower pH it is assigned to a direct attack of water on the substrate. The rate of hydrolysis of 4-acetoxy-3-nitrobenzoic acid is proportional to the catalyst concentration [IIc] and proceeds as a first-order reaction. The hydrolysis depends on the composition of the solvent and was highest at 28.5% (vol.) of ethanol in water. The hydrolysis of a neutral ester, 4-nitrophenyl acetate, was not accelerated by IIc.

Sign in / Sign up

Export Citation Format

Share Document