The Esterolytic Activity of Poly(1-methyl-4- and -5-vinylimidazole) in Water

1975 ◽  
Vol 8 (4) ◽  
pp. 416-424 ◽  
Author(s):  
C. G. Overberger ◽  
Thomas W. Smith
Keyword(s):  
Esterolytic Activity

Cold Promoted Activation of Factor VII

1972 ◽  
Vol 28 (02) ◽  
pp. 169-181 ◽  
Author(s):  
H Gjønnæss
Keyword(s):  
Low Temperature ◽  
Oral Contraceptives ◽  
Fold Increase ◽  
Factor Vii ◽  
Plasma Kallikrein ◽  
Factor Xii ◽  
Overnight Incubation ◽  
Esterolytic Activity

SummaryThe activating principle (CPA) of the factor VII activation seen in plasmas of women taking oral contraceptives after overnight incubation of the plasmas at 0° C was investigated. The reaction was dependent on low temperature, and factor XII was indispensable. Concomitant with the activation of factor VII a 10–30 fold increase in TAME esterolytic activity was observed together with a near 100 per cent drop in plasma kininogen concentration. The results indicated that the activation of factor VII is linked to activation of the kallikrein system, and that the activator may be plasma kallikrein.

Thiol derivatives of cellulose as supports for the immobilization of non-thiol enzymes

1981 ◽  
Vol 46 (7) ◽  
pp. 1693-1700 ◽  
Author(s):  
Peter Gemeiner ◽  
Jiří Zemek
Keyword(s):  
Exchange Reaction ◽  
Proteolytic Activity ◽  
Acetylcholine Esterase ◽  
Mercaptoacetic Acid ◽  
Thiol Groups ◽  
Nucleophilic Reaction ◽  
Disulfide Exchange ◽  
Immobilized Trypsin ◽  
Esterolytic Activity ◽  
Derivatives Of

Thiosulfate derivatives, which can be reduced with mercaptoacetic acid, are suitable intermediates for the preparation of thiol derivatives of polymers. Thiosulfate derivatives of cellulose were prepared via chlorodeoxy- or via 3-chloro-2-hydroxy-propylcellulose, while mercaptodeoxycellulose prepared via chlorodeoxy derivative had more convenient properties for the immobilization of non-thiol enzymes (acetylcholine esterase, butyrylcholine esterase and trypsin). Before immobilization SH groups were introduced into choline esterases by i) reduction of the cystine residues, ii) reaction with methyl 4-mercaptobutyrimidate, and the isothiocyanate groups were introduced into trypsin on reaction with 3-isothiocyanatopropyl 1-isocyanate. The immobilization of the enzymes treated in this way was carried out under the conditions of the oxidation of thiol groups (i), thiol-disulfide exchange reaction (ii), or an addition nucleophilic reaction of isothiocyanates with thiols. In contrast to the proteolytic activity of the immobilized trypsin the esterolytic activity of immobilized choline esterases attained satisfactory values.

Effects of organic solvents on immobilized enzyme catalyses. Chymotrypsin immobilized on porous glass

1981 ◽  
Vol 59 (19) ◽  
pp. 2921-2925 ◽  
Author(s):  
J. Bryan Jones ◽  
Diana H. Pliura
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Porous Glass ◽  
Immobilized Enzyme ◽  
Butyl Alcohol ◽  
Solvent Concentration ◽  
Marked Contrast ◽  
Practical Applications ◽  
Tert Butyl Alcohol ◽  
Esterolytic Activity

The esterolytic activity of native chymotrypsin (CT) immobilized on ionically neutral porous glass beads has been studied in the presence of up to 20% (v/v) of the organic solvents methanol, ethanol, 2-propanol, tert-butyl alcohol, dioxane, and DMSO. In marked contrast to the variations observed with native CT, inhibition of CT immobilized on glass (CT–glass) was independent of the nature of the organic solvent. The overall activity, as indicated by kc(app)/km(app), decreased by 35–50% as the concentration of all solvents surveyed was increased up to 20%. In general, high organic solvent concentration accelerated the rate of protein release from the insoluble catalyst. For practical applications in aqueous organic solvents CT–glass conjugates are inferior to those of the enzyme attached to Sephadex.

Inhibition by Ions of the Esterolytic Activity of Horse Urinary Kailikrein

Pharmacology ◽  
1966 ◽  
Vol 15 (4) ◽  
pp. 389-398 ◽  
Author(s):  
Cylene Kramer ◽  
Eline S. Prado ◽  
J.L. Prado
Keyword(s):  
Esterolytic Activity

Clotting And Chromogenic Substrate Assays Measure Separate Thrombin Activities

1981 ◽  
Author(s):  
M P Milad ◽  
H I Hassouna
Keyword(s):  
Protease Inhibitor ◽  
Blood Coagulation ◽  
Active Site ◽  
Esterase Activity ◽  
Synthetic Peptides ◽  
Important Implication ◽  
Antithrombin Iii ◽  
Chromogenic Substrate ◽  
Functional Sites ◽  
Esterolytic Activity

Thrombin, the final serine protease responsible for the conversion of fibrinogen to fibrin, is known to have the ability to cleave other peptides in addition to those involved in blood coagulation. Many synthetic substrates were devised to be acted on by thrombin reflecting esterolytic, amidolytic and other cleaving properties. Antithrombin III, the major protease inhibitor of plasma, has been shown to bind the proteolytic properties of thrombin irreversibly. The purpose of this study was to determine whether all enzymatic properties are destroyed simultaneously or whether the inhibitor binds the active site leaving esterolytic functions intact.Purified α-thrombin was examined with fibrinogen, and H-D-Phe-Pip-arg-p-nitroanilide assays to prepare standard working curves relating units thrombin to the rate of fibrin endpoint or to the rate of production of chromophore. Then progressive antithrombin inactivation of seryl residue was examined by increasing concentrations of ATIII incubated with thrombin for five minutes and aliquots simultaneously examined for the ability to clot a standard fibrinogen solution and to cleave the synthetic substrate.The clotting activity decreased steadily with increasing antithrombin, whereas the esterase activity remained constant. The study provides further evidence to the observations of Chang et al (Biochemistry 18: 113, (1979)) that thrombin contains two functional sites, one highly specific for the fibrinopeptide region of fibrinogen and the second site relatively nonspecific, responsible for thrombin’s esterolytic activity. An important implication of this study is that clotting assays and chemical assays that use synthetic peptides reflect separate functional properties of the enzyme thrombin.

Esterolytic activity of vinylimidazole-vinylpyrrolidinone copolymers

Biopolymers ◽  
1968 ◽  
Vol 6 (10) ◽  
pp. 1417-1424 ◽  
Author(s):  
Kenneth D. Kopple
Keyword(s):  
Esterolytic Activity

Chromogenic Assays for the Determination of Prothrombin Related Material in Rat Liver Fractions.

1979 ◽  
Author(s):  
Linda J Beecroft
Keyword(s):  
Rat Liver ◽  
Vitamin K ◽  
Microsomal Fraction ◽  
Liver Homogenate ◽  
Chromogenic Substrates ◽  
Related Material ◽  
Esterolytic Activity ◽  
Echis Carinatus ◽  
Microsomal Pellet

Clotting assays are not easily applied to turbid solutions such as microsomal fractions. With the development of chromogenic substrates, the esterolytic activity of prothrombin related material can be assayed biochemically in such systems. Liver fractions were prepared by differential centrifugaron. Liver homogenate was centrifuged at 10,000 g. for 10 minutes to yield supernatant 1.Supernatant 1 was further centrifuged at 105,000 g for 60 minutes to yield the microsomal pellet and supernatant 2. Taipan and Echis carinatus snake vanoms were used to generate esterolytic activity in the various liver fractions. In all fractions the esterolytic activity generated by E. carinatus venom was greater than that generated by Taipan Venom. Both assays indicated that the microsomal pellet had similar esterolytic activity to supernatant 2. When liver fractions were prepared from warfarin treated rats, the assays revealed that the relative proportions of prothrombin related material in the fractions had altered. The esterolytic activity of the microsomal fraction was found to be greatly increased whilst supernatant 2 had no detectable activity.Warfarin treated rats have greatly decreased levels of prothrombin in the plasma due to inhibition of vitamin K-dependent carboxylation in the liver. It is suggested that the lack of prothrombin in the plasma reflects the lack of soluble prothrombin in supernatant 2, and the concomitant build-up of precursor forms bound to the microsomes.

Kinin-generating and esterolytic activity of purified human urinary kallikrein (urokallikrein)

1977 ◽  
Vol 26 (20) ◽  
pp. 1893-1900 ◽  
Author(s):  
Onesmo ole-MoiYoi ◽  
K.Frank Austen ◽  
Jocelyn Spragg
Keyword(s):  
Urinary Kallikrein ◽  
Esterolytic Activity
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