THE EFFECT OF GLYCEROL MEDIUM ON THE ACTIVATION OF HUMAN PLASMINOGEN BY STREPTOKINASE AND ON THE ACTION OF THE ENZYME, PLASMIN

1962 ◽  
Vol 40 (9) ◽  
pp. 1203-1212 ◽  
Author(s):  
Phyllis S. Roberts
Keyword(s):  
Methyl Ester ◽  
Phosphate Buffer ◽  
Water Medium ◽  
Rate Of Hydrolysis ◽  
Human Plasminogen ◽  
Lag Period ◽  
Hydrolysis Of ◽  
Glycerol Medium

A 50% glycerol medium affected the activation of plasminogen by streptokinase (SK) and the activity of plasmin (formed by glycerol incubation) on p-toluene-sulphonyl-L-arginine methyl ester (TAMe) in the following ways:(1) TAMe interfered strongly with the activation of plasminogen by SK in a glycerol medium but not in a water medium under the same conditions.(2) SK inhibited the action of plasmin on TAMe in a glycerol medium, but in a water medium SK increased the rate of hydrolysis of TAMe, the extent of the increase depending upon pH.(3) Phosphate buffer inhibited the activation of plasminogen by SK in a glycerol medium but not in a water medium. In the glycerol medium a lag period in the formation of enzyme was found, particularly noted with a phosphate buffer, and the lag period increased with increasing concentration of the buffer.(4) Phosphate buffer inhibited the action of plasmin on TAMe in a glycerol medium but not in a water medium.Mechanisms of activation of plasminogen by SK are discussed. The data presented support the postulate that a reaction takes place between plasmin and SK to form an enzyme called "activator".

THE EFFECT OF GLYCEROL MEDIUM ON THE ACTIVATION OF HUMAN PLASMINOGEN BY STREPTOKINASE AND ON THE ACTION OF THE ENZYME, PLASMIN

1962 ◽  
Vol 40 (1) ◽  
pp. 1203-1212 ◽  
Author(s):  
Phyllis S. Roberts
Keyword(s):  
Methyl Ester ◽  
Phosphate Buffer ◽  
Water Medium ◽  
Rate Of Hydrolysis ◽  
Human Plasminogen ◽  
Lag Period ◽  
Hydrolysis Of ◽  
Glycerol Medium

A 50% glycerol medium affected the activation of plasminogen by streptokinase (SK) and the activity of plasmin (formed by glycerol incubation) on p-toluene-sulphonyl-L-arginine methyl ester (TAMe) in the following ways:(1) TAMe interfered strongly with the activation of plasminogen by SK in a glycerol medium but not in a water medium under the same conditions.(2) SK inhibited the action of plasmin on TAMe in a glycerol medium, but in a water medium SK increased the rate of hydrolysis of TAMe, the extent of the increase depending upon pH.(3) Phosphate buffer inhibited the activation of plasminogen by SK in a glycerol medium but not in a water medium. In the glycerol medium a lag period in the formation of enzyme was found, particularly noted with a phosphate buffer, and the lag period increased with increasing concentration of the buffer.(4) Phosphate buffer inhibited the action of plasmin on TAMe in a glycerol medium but not in a water medium.Mechanisms of activation of plasminogen by SK are discussed. The data presented support the postulate that a reaction takes place between plasmin and SK to form an enzyme called "activator".

Hydrolysis of L-Histidine Methyl Ester

1968 ◽  
Vol 19 (03/04) ◽  
pp. 334-345
Author(s):  
E. R Cole
Keyword(s):  
Methyl Ester ◽  
Esterase Activity ◽  
Activity Ratio ◽  
Proteolytic Enzymes ◽  
Relative Affinity ◽  
Human Plasminogen ◽  
High Concentrations ◽  
Autoprothrombin C ◽  
Hydrolysis Of ◽  
Activator Complex

SummaryThe ratio of TAME esterase activity (or PME esterase activity for α-chymotrypsin) to HME esterase activity has been determined for a number of proteolytic enzymes under identical conditions. Papain showed no attack on HME, but ficin, bromelin, human plasmin, trypsin, thrombin, autoprothrombin C, urokinase and α-chymotrypsin hydrolyze this substrate to varying degrees. Ficin showed a TAME/HME activity ratio of 304 while the lowest ratio (approximately 1) was found for urokinase, an activator of plasminogen. This high relative affinity of urokinase for HME prompted an investigation to determine if this property was also a function of streptokinase-activator complex. Glycerol-activated plasmin had a low relative affinity for HME as a substrate (TAME/HME = 157), but addition of high concentrations of streptokinase increased the relative affinity of the preparation for HME catalysis by 500 to 600% (TAME/HME = 26.4). Human plasminogen activated by high concentrations of streptokinase also demonstrate high relative affinity for HME (TAME/ HME = 20-25). HME esterase activity is largely lost when streptokinase is destroyed by pH 2.0 treatment, but can be regained by readdition of streptokinase to the plasmin preparation. Hydrolysis of HME by plasmin preparations in the presence of streptokinase is believed to be primarily a property of streptokinase-plasmin complex.

Kinetics of hydrolysis of dispersions of saturated phosphatidylcholines by Crotalus atrox phospholipase A2

1978 ◽  
Vol 56 (6) ◽  
pp. 552-558 ◽  
Author(s):  
David O. Tinker ◽  
A. David Purdon ◽  
Jane Wei ◽  
Eileen Mason
Keyword(s):  
Liquid Crystalline ◽  
Phase Reaction ◽  
Reaction Products ◽  
Crotalus Atrox ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Desorption Rate Constant ◽  
Rate Of Hydrolysis ◽  
Lag Period ◽  
Lipid Surface ◽  
Hydrolysis Of

Dispersions of lamellar phase dipalmitoyl phosphatidylcholine (DDPC) and dimyristoyl phosphatidylcholine (DMPC) in 0.01 M CaCl2 were subjected to hydrolysis by phospholipase A2 (EC 3.1.1.4) from Crotalus atrox venom. The reaction was followed continuously by titrating the released fatty acids. For hydrolysis of gel phase phosphatides, the steady-state initial velocities were hyperbolic functions of bulk lipid concentrations. At the 'pre-transition' temperature (34 °C for DPPC, 15 °C for DMPC), there was a large increase in the Michaelis parameter Vmax but no change in the parameter Km. A model was devised to account for these observations, in which the enzyme desorbs from the lipid surface after hydrolysis. The desorption rate constant is postulated to increase above the pretransition temperature.For hydrolysis of liquid crystalline phosphatides, the reaction consisted of a short initial burst of hydrolysis, a long 'lag' period of very slow reaction, followed by a dramatic increase in the reaction rate. Addition of 10 mol% lysolecithin or fatty acid abolished the 'lag' period. It was postulated that the enzyme adsorbs irreversibly to the surface of the liquid crystalline phase. Reaction products are postulated to stimulate desorption of enzyme from the surface. Thus, temperature-dependent changes in the rate of hydrolysis of dispersed phosphatidylcholines are attributed to changes in the rate of desorption of the enzyme from the lipid surface.

The Effects of Biguanides on Thrombokinase, Thrombin and Trypsin

1975 ◽  
Vol 34 (01) ◽  
pp. 246-255
Author(s):  
Phyllis S Roberts ◽  
Patricia B Fleming
Keyword(s):  
Methyl Ester ◽  
Enzymatic Activity ◽  
Test Period ◽  
Factor X ◽  
Bovine Thrombin ◽  
Slow Reaction ◽  
Bovine Trypsin ◽  
Rate Of Hydrolysis ◽  
Almost All ◽  
Hydrolysis Of

SummaryA purified preparation of bovine thrombokinase (activated Factor X) loses the ability to hydrolyze TAME (p-toluenesulfonyl-L-arginine methyl ester) when it is incubated at 37° in 0.25 M Tris. HCl buffer, pH 7.4 with lauroxypropyl biguanide, N1, N5-dimethyl, N1-lauroxypropyl biguanide, N1-p-chlorophenethyl, N5-phenethyl biguanide, or N1-methyl, N1-p-chlorobenzyl, N5-o,p-dichlorobenzyl biguanide. Activity is lost much more slowly when 0.15 M NaCl is also present. Lauroxypropyl biguanide is the most potent of the compounds tested, 0.22 mM causing thrombokinase to lose almost all of its activity in about 30 minutes at 37° in pH 7.4 buffered saline.Topical bovine thrombin also loses activity when incubated with either of the lauroxypropyl biguanides but not with the diphenethyl or the dibenzyl compound. Instead, the latter biguanides accelerate thrombin’s hydrolysis of TAME. The percent acceleration is not affected or only slightly decreased by the presence of 0.15 M NaCl or KCl, and it is also unaffected by incubating the enzyme with the compounds in buffered saline for 4 to 120 minutes.Purified bovine trypsin is stabilized by both lauroxypropyl and the diphenethyl biguanide when incubated at 37° in pH 7.4 buffered saline for the 60 minute test period but neither compound has any effect on its rate of hydrolysis of TAME.It is postulated that the enzymes first react rapidly and reversibly with all of the test biguanides and, depending upon the enzyme and the substrate, the rate of hydrolysis of the substrate is unaffected, accelerated or inhibited. The lauroxypropyl biguanides also undergo a second, slower reaction with both thrombokinase and thrombin that produces loss of enzymatic activity. The dibenzyl and diphenethyl biguanides also undergo this second slow reaction with thrombokinase but not with thrombin, and none of the biguanides undergo this second reaction with trypsin.

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.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

Polarographic study of hydrolysis of [8-lysine]vasopressin and its derivatives with blood serum of pregnant women

1980 ◽  
Vol 45 (4) ◽  
pp. 1099-1108 ◽  
Author(s):  
Mikuláš Chavko ◽  
Michal Bartík ◽  
Evžen Kasafírek
Keyword(s):  
Blood Serum ◽  
Pregnant Women ◽  
Degree Of Hydrolysis ◽  
Polarographic Study ◽  
Ph Optimum ◽  
Lysine Vasopressin ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Vasopressin Analogues

A polarographic study of the hydrolysis of [8-lysine]vasopressin and some hormonogens of the vasopressin series with the blood serum of women in the last week of pregnancy was studied. The dependence of hydrolysis on pH (pH optimum: 7.4-7.50, substrate concentration (Km 1.2 . 10-5M), pH stability and thermal stability were determined. The rate of hydrolysis of individual vasopressin analogues decreases in the order: [8-lysine]vasopressin > Nα-glycyl-prolyl[8-lysine]-vasopressin > Nα-leucyl-[8-lysine]vasopressin > Nα-alanyl-[8-lysine]vasopressin > Nα-phenyl alanyl-[8-lysine]vasopressin > Nα-diglycyl-[8-lysine]vasopressin > Nα-prolyl-[8-lysine]vasopressin > Nα-triglycyl-[8-lysine]vasopressin > Nα-sarcosyl-glycyl-[8-lysine]vasopressin. The degree of hydrolysis gradually increases to a multiple with the length of the pregnancy in consequence of the presence of oxytocine. However, vasopressin is also hydrolysed to a small extent with the enzymes from the blood sera of non-pregnant women. Under similar analytical conditions oxytocin was not hydrolysed with the sera of non-pregnant women and therefore oxytocin is a more suitable substrate than vasopressin for polarographic determination of serum oxytocinase.

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