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

Catalysis at the toluene/water interface: shape-selective hydrolysis of esters having some rings and lactones promoted by octadecyl immobilized H-ZSM-5 catalyst

1996 ◽  
Vol 41 (3-4) ◽  
pp. 177-179 ◽  
Author(s):  
Haruo Ogawa ◽  
Tamiki Fujigaki ◽  
Junichi Takahashi ◽  
Teiji Chihara
Keyword(s):  
Water Interface ◽  
Interface Shape ◽  
Selective Hydrolysis ◽  
Shape Selective ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

ChemInform Abstract: Bi(III) as New Catalyst for the Selective Hydrolysis of Esters.

ChemInform ◽  
2010 ◽  
Vol 28 (32) ◽  
pp. no-no
Author(s):  
V. LE BOISSELIER ◽  
M. POSTEL ◽  
E. DUNACH
Keyword(s):  
Selective Hydrolysis ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

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.

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