Inactivation of bovine thrombin by nitrous acid

1970 ◽  
Vol 48 (4) ◽  
pp. 432-437 ◽  
Author(s):  
S. Magnusson ◽  
T. Hofmann
Keyword(s):  
Ethyl Ester ◽  
Esterase Activity ◽  
Nitrous Acid ◽  
Initial Rate ◽  
Serine Proteinases ◽  
Bovine Thrombin ◽  
Partial Protection ◽  
Isoleucine Residue ◽  
Full Protection ◽  
Prothrombin Activation

Bovine thrombin is rapidly inactivated by nitrous acid at pH 4.35 and 0°. The clotting activity falls off more rapidly than the activity towards N-benzoylarginine ethyl ester. The loss of esterase activity parallels the loss of the N-terminal isoleucine residue. N-Benzoylarginine ethyl ester gives almost full protection of the esterase activity and the N-terminal isoleucine, but only partial protection of the clotting activity. These results suggest strongly that this residue is essential for activity and indicate that thrombin resembles the pancreatic serine proteinases in this respect. The initial rate of inactivation of thrombin by nitrous acid is higher than that of trypsin, and considerably higher than that of elastase and α-chymotrypsin under the same conditions, suggesting that the N-terminal residue is more readily accessible to the reagent. The experiments strengthen the hypothesis that all mechanisms of prothrombin activation are proteolytic and suggest that they involve the liberation of the essential N-terminal isoleucine.

Amino-terminal groups in zymogen activation: effect of nitrous acid on pepsin

1969 ◽  
Vol 47 (12) ◽  
pp. 1099-1101 ◽  
Author(s):  
T. Hofmann
Keyword(s):  
Nitrous Acid ◽  
Lysine Residue ◽  
Amino Group ◽  
Serine Proteinases ◽  
Zymogen Activation ◽  
Activation Effect ◽  
Amino Terminal ◽  
Tryptophan Residues ◽  
Terminal Amino ◽  
Isoleucine Residue

Nitrous acid rapidly deaminates the N-terminal isoleucine residue of pepsin. The enzyme retains more than 60% of its activity. The loss of 30–40% activity can be ascribed to the reaction of two tryptophan residues with nitrous acid. The single lysine residue is also deaminated. These results are in contrast to those obtained with serine proteinases where nitrous acid causes inactivation due to the deamination of the N-terminal amino group.

scholarly journals Activities of Acyclic Nucleoside Phosphonates against Orf Virus in Human and Ovine Cell Monolayers and Organotypic Ovine Raft Cultures

2005 ◽  
Vol 49 (12) ◽  
pp. 4843-4852 ◽  
Author(s):  
F. Dal Pozzo ◽  
G. Andrei ◽  
A. Holý ◽  
J. Van Den Oord ◽  
A. Scagliarini ◽  
...  
Keyword(s):  
Orf Virus ◽  
Human Embryonic Lung ◽  
Raft Culture ◽  
Partial Protection ◽  
Cell Monolayers ◽  
Hel Cells ◽  
Acyclic Nucleoside Phosphonates ◽  
Acyclic Nucleoside ◽  
Virus Strains ◽  
Full Protection

ABSTRACT Orf virus, a member of the Parapoxvirus genus, causes a contagious pustular dermatitis in sheep, goats, and humans. Previous studies have demonstrated the activity of (S)-1-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine (HPMPC; cidofovir; Vistide) against orf virus in cell culture and humans. We have evaluated a broad range of acyclic nucleoside phosphonates (ANPs) against several orf virus strains in primary lamb keratinocytes (PLKs) and human embryonic lung (HEL) monolayers. HPMPC, (S)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6- diaminopurine (HPMPDAP), and (R)-9-[3-hydroxy-2-(phosphonomethoxy)propoxy]-2,4-diaminopyrimidine (HPMPO-DAPy) were three of the most active compounds that were subsequently tested in a virus yield assay with PLK and HEL cells by virus titration and DNA quantification. HPMPC, HPMPDAP, and HPMPO-DAPy were evaluated for their activities against orf virus replication in organotypic epithelial raft cultures from differentiated PLK cells. At the highest concentrations (50 and 20 μg/ml), full protection was provided by the three drugs, while at 5 μg/ml, only HPMPDAP and HPMPC offered partial protection. The activities of the three compounds in the raft culture system were confirmed by quantification of infectious virus and viral DNA. These findings provide a rationale for the use of HPMPC and other ANPs in the treatment of orf (contagious ecthyma) in humans and animals.

AUTOPROTHROMBIN C: A SECOND ENZYME FROM PROTHROMBIN

1962 ◽  
Vol 40 (1) ◽  
pp. 597-605 ◽  
Author(s):  
Ewa Marciniak ◽  
Walter H. Seegers
Keyword(s):  
Calcium Ions ◽  
Esterase Activity ◽  
Sodium Citrate ◽  
Citrate Solution ◽  
Tissue Extracts ◽  
End Products ◽  
Ph Range ◽  
Autoprothrombin C ◽  
Prothrombin Activation ◽  
Rapid Conversion

In addition to thrombin, there is another derivative of prothrombin which is an end product of prothrombin activation. It is an accelerator of prothrombin activation, and is called autoprothrombin C. The activity develops from purified bovine prothrombin in 25% sodium citrate solution simultaneously with thrombin. It has been separated from thrombin by chromatography on Amberlite IRC-50 under the conditions previously used for the isolation of thrombin. The fraction which separates from thrombin has esterase activity and very likely this esterase activity is associated with the autoprothrombin C molecule. Since the autoprothrombin C and the thrombin are both derived from prothrombin, at least two enzymes are the end products of prothrombin activation. Autoprothrombin C catalyzed the activation of purified prothrombin in 25% sodium citrate solution, and this function was easily inhibited with p-toluenesulphonyl-L-arginine methyl ester. Autoprothrombin C preparations were mixed with platelets, Ac-globulin, and calcium ions to obtain rapid conversion of purified prothrombin to thrombin. This activation mixture did not generate autoprothrombin C and some unspecified substance most likely needs to be added in order to obtain the autoprothrombin C activity. The activity developed together with thrombin when tissue extracts, Ac-globulin, and calcium ions were used for the activation of prothrombin. Autoprothrombin C is relatively stable over the pH range 5.5 to 8.5. It is stable up to 56 °C for 30 minutes. Plasma contains a substance that inactivates autoprothrombin C.

SOME PROPERTIES OF THROMBIN PREPARATIONS

1959 ◽  
Vol 37 (1) ◽  
pp. 775-785 ◽  
Author(s):  
Walter H. Seegers ◽  
Gerardo Casillas ◽  
Robert S. Shepard ◽  
William R. Thomas ◽  
Paul Halick
Keyword(s):  
Esterase Activity ◽  
Sodium Citrate ◽  
Citrate Solution ◽  
Ideal Model ◽  
Terminal Amino Acid ◽  
Two Stage ◽  
Analytical Reagents ◽  
Terminal Amino ◽  
Autocatalytic Activation ◽  
Prothrombin Activation

Bio-resin thrombin preparations were found to contain three weak precipitinogens. The clotting activity was not demonstrably associated with the precipitinogenic systems. Further, work was done on methods for the purification of citrate resin thrombin, and its clotting activity is also not associated with a precipitinogenic system. The N-terminal amino acid of both bio-resin thrombin and citrate resin thrombin was found to be glutamic acid. The two preparations were found to be homogeneous upon ultracentrifugal examination and could not be differentiated on the basis of sedimentation constants. Since "citrate" activation and "bio" activation produce eventually similar thrombin material, the autocatalytic activation of prothrombin in 25% sodium citrate solution can be used as an ideal model of prothrombin activation. The prothrombin first dissociates to form a derivative that does not form thrombin in the two-stage analytical reagents. Then a second alteration occurs in which the derivative again may form thrombin in the two-stage analytical reagents. Then thrombin activity appears as esterase activity, then as clotting activity. Later the clotting activity may be lost and finally also the esterase activity. The original prothrombin is a precipitinogen while the active thrombin is not.

Kinetics of the Reaction of Nitrous Acid with Model Compounds and Proteins, and the Conformational State of N-terminal Groups in the Chymotrypsin Family

1972 ◽  
Vol 50 (12) ◽  
pp. 1282-1296 ◽  
Author(s):  
A. Kurosky ◽  
T. Hofmann
Keyword(s):  
Nitrous Acid ◽  
Conformational State ◽  
Serine Proteinases ◽  
Amino Groups ◽  
Model Compounds ◽  
Third Order ◽  
Tyrosine Residues ◽  
Reactive Groups ◽  
Primary Amino ◽  
Kinetics Of

The kinetics of the reaction of nitrous acid at 4° and pH 4.0 with various amino acids, peptides, and proteins were studied. The reaction with isoleucine methyl ester was found to have a linear dependence on the square of the HONO concentration showing that N2O3 was the reactive species. Third order nitrosation rate constants of primary amino groups showed a correlation with their pK values. They were calculated for the concentration of the unprotonated species to give intrinsic reactivities. The rate of nitrosation of acetyltryptophan to give N-nitrosoacetyltryptophan was found to be a linear function of the nitrous acid concentration. This nitrosation therefore follows a different mechanism. The reaction of nitrous acid with tyrosine residues was examined by spectrophotometry. The reaction was negligible compared to that of other groups. Acetylhistidine and imidazole did not react. Reactivities for α-amino groups, ε-amino groups, and other residues in proteins were compared. The conformational state of the N-terminal residues in serine proteinases, as revealed from their reactivities, is discussed in detail. It is concluded that nitrous acid reacts preferentially with "surface" residues and is a useful tool for exploring conformational states of reactive groups in proteins, especially α-amino groups and indole rings.

scholarly journals Notes on the distribution of lichen biota of Podlasie. III. Nowosady village, Podlaskie province (north-eastern Poland)

2015 ◽  
Vol 50 (1) ◽  
Author(s):  
Sylwia Kiercul
Keyword(s):  
Lichen Species ◽  
Tree Bark ◽  
Evernia Prunastri ◽  
Partial Protection ◽  
Lichen Biota ◽  
North Eastern ◽  
Statutory Protection ◽  
Surrounding Areas ◽  
Ramalina Farinacea ◽  
Full Protection

<p>The present study was undertaken to evaluate the biodiversity of lichen species in Nowosady village and surrounding areas. This work was conducted in 2014 (in August) and biodiversity of lichen species growing on tree bark and bushes, on dead wood (anthropogenic origin), glacial erratics, concrete, mortared walls and other specific substrates like eternit roof slates has been assessed. The lichen species represented morphologically diverse forms: crustose (38%), foliose (38%), fruticose (13%), dimorphous (5%), placodial (3%) and squamulose (3%). They belonged to different ecological types including epiphytes (27 species), epixyles (18) and epilithes (12). Out of 39 species identified in Nowosady village, five are included in the Polish red list of lichens: <em>Bryoria fuscescens</em>, <em>Evernia prunastri</em>, <em>Hypogymnia tubulosa</em>, <em>Ramalina farinacea</em> and <em>Ramalina fraxinea</em>. Four taxons from the study area are under statutory protection of species. One species, <em>Ramalina fraxinea</em> is under full protection and 3 species (<em>Bryoria fuscescens</em>, <em>Evernia prunastri</em> and <em>Hypogymnia tubulosa</em>) are under partial protection.</p>

scholarly journals Survey on 3D Content Encryption

2021 ◽  
Vol 15 (15) ◽  
pp. 115
Author(s):  
Nashwan Alsalam Ali ◽  
Abdul Monem S. Rahma ◽  
Shaimaa H. Shaker
Keyword(s):  
Chaotic Maps ◽  
3D Models ◽  
The Internet ◽  
Partial Protection ◽  
Encryption Schemes ◽  
3D Applications ◽  
And Diffusion ◽  
Confusion And Diffusion ◽  
Full Protection ◽  
3D Content

<p class="0abstract">The rapidly growing 3D content exchange over the internet makes securing 3D content became a very important issue. The solution for this issue is to encrypting data of 3D content, which included two main parts texture map and 3D models. The standard encryption methods such as AES and DES are not a suitable solution for 3D applications due to the structure of 3D content, which must maintain dimensionality and spatial stability. So, these problems are overcome by using chaotic maps in cryptography, which provide confusion and diffusion by providing uncorrelated numbers and randomness. Various works have been applied in the field of 3D content-encryption based on the chaotic system. This survey will attempt to review the approaches and aspects of the structure used for 3D content encryption methods for different papers. It found the methods that used chaotic maps with large keyspace are more robust to various attacks than other methods that used encryption schemes without chaotic maps. The methods that encrypting texture, polygon, and vertices for 3D content provide full protection than another method that provides partial protection.</p>

Human Plasma and Serum Trypsin-like Esterase Activity

1966 ◽  
Vol 12 (6) ◽  
pp. 350-359 ◽  
Author(s):  
Roman B Rutkowski
Keyword(s):  
Calcium Oxalate ◽  
Human Plasma ◽  
Ethyl Ester ◽  
Trypsin Inhibitor ◽  
Spectrophotometric Method ◽  
Esterase Activity ◽  
Soybean Trypsin Inhibitor ◽  
Serum Trypsin ◽  
Healthy Males

Abstract A spectrophotometric method using benzoyl arginine ethyl ester (BAEE) is described for the assay of serum and plasma trypsin-like esterase activity. The method was used to find activities in serum and plasma (anticoagulated with oxalate and heparin) from 12 healthy males at 3 different reaction pH's. The effects of calcium, oxalate, heparin, soybean trypsin inhibitor, ovomucoid, and heat on this activity were also measured. Values of esterase activity were significantly different, indicating a variable enzyme or inhibitor composition in the 3 sets of samples. Plasma from heparinized blood gave unique activity responses to pH and to the agents tested for effect.

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