THE ACETYLATION OF PROTHROMBIN

1960 ◽  
Vol 38 (6) ◽  
pp. 613-620 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Calcium Ions ◽  
Sodium Citrate ◽  
Brain Extract ◽  
Amino Groups ◽  
Ph Optimum ◽  
Platelet Factor ◽  
Alkaline Side ◽  
Proportionate Change ◽  
Hydrolysis Of ◽  
Zero Time

Purified bovine prothrombin was acetylated to a range of 27 to 30% of its amino groups. Except for just significant amounts it lost its power to generate thrombin-C. Upon activation the yield of thrombin-E was 100% on the basis of the thrombin-C yield that was obtained on an aliquot sample of the prothrombin before acetylation. Activation was achieved in 25% sodium citrate solution, with calcium ions plus brain extract thromboplastin, and with calcium ions plus protein-free brain thromboplastin. Evidently no Ac-globulin was needed; however, a concentrate of Ac-globulin accelerated the activation. The pH optimum for activation with brain extract thromboplastin is more to the alkaline side than with prothrombin. Activation with purified platelet factor 3 was quite slow, but was accelerated by adding a small amount of thrombin-E, in the form of acetylated thrombin, at zero time. Thrombin-C did not function in that capacity. A change in prothrombin had to be accompanied by a proportionate change in the thrombin to have the latter serve as a catalyst in the activation. Ac-globulin accelerates the hydrolysis of p-toluenesulphonyl-L-arginine methyl ester by thrombin. Ac-globulin owes its activity to thrombin. The view is expressed that Ac-globulin is measured as accelerated thrombin activity in the activation of prothrombin. In other words Ac-globulin accelerates the activation of acetylated prothrombin by thrombin-E. The amino groups on the N-terminal glutamic acid residues are free in the thrombin-E obtained from acetylated prothrombin. It is possible to acetylate an amino group in prothrombin that is necessary for thrombin-C activity.

THE ACETYLATION OF PROTHROMBIN

1960 ◽  
Vol 38 (1) ◽  
pp. 613-620 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Calcium Ions ◽  
Sodium Citrate ◽  
Brain Extract ◽  
Amino Groups ◽  
Ph Optimum ◽  
Platelet Factor ◽  
Alkaline Side ◽  
Proportionate Change ◽  
Hydrolysis Of ◽  
Zero Time

Purified bovine prothrombin was acetylated to a range of 27 to 30% of its amino groups. Except for just significant amounts it lost its power to generate thrombin-C. Upon activation the yield of thrombin-E was 100% on the basis of the thrombin-C yield that was obtained on an aliquot sample of the prothrombin before acetylation. Activation was achieved in 25% sodium citrate solution, with calcium ions plus brain extract thromboplastin, and with calcium ions plus protein-free brain thromboplastin. Evidently no Ac-globulin was needed; however, a concentrate of Ac-globulin accelerated the activation. The pH optimum for activation with brain extract thromboplastin is more to the alkaline side than with prothrombin. Activation with purified platelet factor 3 was quite slow, but was accelerated by adding a small amount of thrombin-E, in the form of acetylated thrombin, at zero time. Thrombin-C did not function in that capacity. A change in prothrombin had to be accompanied by a proportionate change in the thrombin to have the latter serve as a catalyst in the activation. Ac-globulin accelerates the hydrolysis of p-toluenesulphonyl-L-arginine methyl ester by thrombin. Ac-globulin owes its activity to thrombin. The view is expressed that Ac-globulin is measured as accelerated thrombin activity in the activation of prothrombin. In other words Ac-globulin accelerates the activation of acetylated prothrombin by thrombin-E. The amino groups on the N-terminal glutamic acid residues are free in the thrombin-E obtained from acetylated prothrombin. It is possible to acetylate an amino group in prothrombin that is necessary for thrombin-C activity.

THE HYDROLYSIS OF MONOPHOSPHOINOSITIDE BY EXTRACTS OF BRAIN

1967 ◽  
Vol 45 (6) ◽  
pp. 853-861 ◽  
Author(s):  
W. Thompson
Keyword(s):  
Fatty Acids ◽  
Enzyme Activity ◽  
Calcium Ions ◽  
Brain Extract ◽  
Monovalent Cations ◽  
High Concentration ◽  
Diffusible Factor ◽  
Hydrolysis Of ◽  
The Brain ◽  
Long Chain

The hydrolysis of monophosphoinositide by soluble extracts from rat brain is described. Diglyceride and inositol monophosphate are liberated along with a small amount of free fatty acids. Hydrolysis of the lipid is optimal at pH 5.4 in acetate buffer. The reaction is stimulated by calcium ions or by high concentration of monovalent cations and, to a less extent, by long-chain cationic amphipathic compounds. Enzyme activity is lost on dialysis of the brain extract and can be restored by diffusible factor(s). Some differences in the conditions for hydrolysis of mono- and tri-phosphoinositides are noted.

Generation of proteolytic activity during activation of prothrombin

1959 ◽  
Vol 197 (6) ◽  
pp. 1178-1180 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Methyl Ester ◽  
Proteolytic Activity ◽  
Esterase Activity ◽  
Proteolytic Enzyme ◽  
Sodium Citrate ◽  
Citrate Solution ◽  
Platelet Factor ◽  
Thrombin Activity ◽  
Hydrolysis Of

In the activation of purified prothrombin with thrombin, with platelet factor 3, or in 25% sodium citrate solution the free thrombin activity which develops is greater at all times when measured by hydrolysis of p-toluenesulfonyl-arginine-methyl ester than when measured by the clotting of fibrinogen. Since the esterase activity appears before clotting power and remains after clotting power is lost, the clotting property must arise from a dissociable complex arising from the unit that has the esterase function. It is postulated that "clotting thrombin" may be a dimer of the lowest subunit of prothrombin required to have the proteolytic enzyme. The latter could have an important function in our physiology quite apart from the clotting of blood.

Activation of Prothrombin

1958 ◽  
Vol 193 (1) ◽  
pp. 169-180 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Calcium Ions ◽  
Esterase Activity ◽  
Sodium Citrate ◽  
Strong Solutions ◽  
Sulfate Solution ◽  
Protamine Sulfate ◽  
Citrate Solution ◽  
Platelet Factor ◽  
Autocatalytic Activation ◽  
Prothrombin Activation

In experiments with purified biothrombin, it was found that strong solutions of sodium citrate or protamine sulfate (0.1% w/v) or purified platelet factor 3 depress the esterase activity and leave the clotting power unaltered. Apparently a depression of esterase activity is beneficial for the autocatalytic activation of purified prothrombin. In protamine sulfate solution, prothrombin gradually becomes thrombin and the yield of thrombin is even higher than in 25% sodium citrate solution. Prothrombin also depresses the esterase activity of biothrombin, and itself serves as a substrate for the enzyme thrombin. When prothrombin becomes an inactive derivative or a substance refractory to being converted to thrombin in the presence of Ac-globulin, thromboplastin and calcium ions, it can nevertheless be changed to thrombin with the use of thrombin as a catalyst, just as was previously accomplished with the use of 25% sodium citrate solutions. Theoretically, a prothrombin derivative(s) can serve as substrate competitor for thrombin and thus be an accelerator of prothrombin activation, or the derivative, under appropriate conditions can itself give rise to thrombin. Thrombin as activator of prothrombin can account for all observed conditions of prothrombin activation. The discovery of thrombin as activator of prothrombin offers a simplified view of the entire blood coagulation mechanisms. Two equations can describe the basic events: Prothrombin(See PDF for Equation)Thrombin; Fibrinogen(See PDF for Equation)Fibrin. Other factors support the production and enzymic function of thrombin and these are called procoagulants. Opposed to these, and normally in exact balance, are those factors that hinder the production or function of thrombin and these are called anticoagulants. In the presence of thrombin prothrombin can change to thrombin without Ac-globulin. Plasma Ac-globulin changes to serum Ac-globulin in the presence of thrombin but not with esterase thrombin. Consequently, the depression of esterase activity does not impair the capacity of thrombin to make the beneficial alteration in Ac-globulin.

Partial Activation of Purified Prothrombin: Derivation of Autoprothrombin I with Use of Autoprothrombin C

1962 ◽  
Vol 07 (02) ◽  
pp. 239-248 ◽  
Author(s):  
Walter H Seegers ◽  
Edmond R Cole ◽  
Ewa Marciniak
Keyword(s):  
Calcium Ions ◽  
Platelet Factor ◽  
Stability Properties ◽  
Partial Activation ◽  
Autoprothrombin C

SummaryActivation of purified prothrombin with autoprothrombin C in the absence of calcium ions produces autoprothrombin I activity. The solubility, and stability properties of this autoprothrombin I are different from those of autoprothrombin I when obtained by activating prothrombin with calcium ions, platelet factor 3, and Ac-globulin.

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.

A simple procedure using trinitrobenzenesulphonic acid for monitoring proteolysis in cheese

1988 ◽  
Vol 55 (4) ◽  
pp. 585-596 ◽  
Author(s):  
Anna Polychroniadou
Keyword(s):  
Simple Procedure ◽  
Water Soluble ◽  
Acid Solutions ◽  
Amino Groups ◽  
Total N ◽  
Cheese Ripening ◽  
Amino Acid Solutions ◽  
Hydrolysis Of ◽  
Good Agreement

SummaryA simple, rapid and sensitive spectrophotometric assay was developed and evaluated for monitoring proteolysis during cheese ripening, based on the fact that α-amino groups released by hydrolysis of cheese proteins react with trinitrobenzenesulphonic acid to form products that absorb strongly at 420 nm. A linear relationship was shown to exist between A420 and concentration of free α amino groups up to 0·5 HIM (r = 0·999, 38 df, P < 0·001). Repeatability of the method was satisfactory. The coefficient of variance was 0·53% for amino acid solutions and 1·19% for cheese extracts. Average recovery of glycine added to the cheese was 104 ± 2·9%. A comparison of the above method with that of determination of water-soluble N to total N ratio showed that there was good agreement between these two methods of assessment of proteolysis in cheese (r = 0·857, 32 df, P < 0·001). Mainly Feta and Teleme cheese were examined, but a similar correlation was obtained with hard Greek cheeses. Analytical conditions of the procedure are discussed.

Dinuclear Zinc(II) Complexes of Linear and Cyclic Peptides Containing Two Bis(2-pyridylmethyl)amino Groups as Catalysts for Hydrolysis of RNA Model Substrate

2001 ◽  
pp. 516-517
Author(s):  
Masao Kawai ◽  
Hatsuo Yamamura ◽  
Nobuko Izuhara ◽  
Tomotsugu Kawaguchi ◽  
Ryoji Tanaka ◽  
...  
Keyword(s):  
Cyclic Peptides ◽  
Amino Groups ◽  
Hydrolysis Of

scholarly journals Biodegradation of low molecular weight polyacrylamide under aerobic and anaerobic conditions: effect of the molecular weight

2020 ◽  
Vol 81 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Wenzhe Song ◽  
Yu Zhang ◽  
Amir Hossein Hamidian ◽  
Min Yang
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Carbon Chain ◽  
Anaerobic Treatment ◽  
Low Molecular Weight ◽  
Amino Groups ◽  
Molecular Weights ◽  
Weight One ◽  
Hydrolysis Of ◽  
Aerobic And Anaerobic

Abstract The biodegradation of polyacrylamide (PAM) includes the hydrolysis of amino groups and cleavage of the carbon chain; however, the effect of molecular weight on the biodegradation needs further investigations. In this study, biodegradation of low molecular weight PAM (1.6 × 106 Da) was evaluated in two aerobic (25 °C and 40 °C) and two anaerobic (35 °C and 55 °C) reactors over 100 days. The removal of the low molecular weight PAM (52.0–52.6%) through the hydrolysis of amino groups by anaerobic treatment (35 °C and 55 °C) was much higher than that of the high molecular weight (2.2 × 107 Da, 11.2–17.0%) observed under the same conditions. The molecular weight was reduced from 1.6 × 106 to 6.45–7.42 × 105 Da for the low molecular weight PAM, while the high molecular weight PAM declined from 2.2 × 107 to 3.76–5.87 × 106 Da. The results showed that the amino hydrolysis of low molecular weight PAM is easier than that of the high molecular weight one, while the cleavage of its carbon chain is still difficult. The molecular weights of PAM in the effluents from the two aerobic reactors (25 °C and 40 °C) were further reduced to 4.31 × 105 and 5.68 × 105 Da by the biofilm treatment, respectively. The results would be useful for the management of wastewater containing PAM.

scholarly journals The Effect of Procoagulative Phospholipids on the Synthetic Substrate Determined Thrombin Generation in Vitro

1977 ◽  
Author(s):  
F. Schulte ◽  
O. Klug ◽  
Ursula Roth
Keyword(s):  
Thrombin Generation ◽  
Chromogenic Substrate ◽  
Chromogenic Substrates ◽  
Platelet Factor ◽  
Synthetic Substrate ◽  
Thrombin Activity ◽  
Vitro Effect ◽  
Hydrolysis Of

The effect of procoagulative phospholipids (Procops) with platelet factor-3 like activity on the generation of thrombin in plasma can be determined in vitro with the aid of synthetic chromogenic substrates. Standard citrated plasma of two manufacturers and from different batches incubated with amounts of 2-10 meg Procops as 1:100 - 1:500 diluted Tachostyptan (micellar Procops in form of a pharmaceutical speciality) was activated. The generated amount of thrombin activity catalyses the hydrolysis of chromogenic substrate to a tripeptide and to p-nitroaniline which was measured kinetically with a spectrophotometer at 405 nm. At optimum concentrations of Procops, activities adequate to 80 (SD ± 7, VK 8. 8%) - 115 i. u. (SD ± 2. 5, VK 2.2%) thrombin per ml plasma were measured depending on the conditions of incubation and activation. Having made the basis of appropriate procedures for incubation and activation the in vitro effect of Procops on the thrombin generation in plasma is reproducibly measurable with the aid of chromogenic substrate.

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