THROMBIN PROPERTIES

1957 ◽  
Vol 35 (1) ◽  
pp. 743-758 ◽  
Author(s):  
Edward Ronwin
Keyword(s):  
Ionic Strength ◽  
Substrate Specificity ◽  
Enzymatic Activity ◽  
Enzymatic Properties ◽  
Organic Reagents

The enzymatic properties of thrombin have been examined and compared with those of two related enzymes, plasmin and trypsin. The effects of factors such as pH, substrate specificity, ionic strength, cations, anions, and organic reagents on the enzymatic activity of thrombin have been studied. While the three enzymes discussed possess differences, such similarities as were observed are quite striking and permit their classification into one group as tryptic enzymes.

THROMBIN PROPERTIES

1957 ◽  
Vol 35 (9) ◽  
pp. 743-758 ◽  
Author(s):  
Edward Ronwin
Keyword(s):  
Ionic Strength ◽  
Substrate Specificity ◽  
Enzymatic Activity ◽  
Enzymatic Properties ◽  
Organic Reagents

The enzymatic properties of thrombin have been examined and compared with those of two related enzymes, plasmin and trypsin. The effects of factors such as pH, substrate specificity, ionic strength, cations, anions, and organic reagents on the enzymatic activity of thrombin have been studied. While the three enzymes discussed possess differences, such similarities as were observed are quite striking and permit their classification into one group as tryptic enzymes.

scholarly journals Studies on separation and properties of lumbrokinase in Pheretima praepinguis

2016 ◽  
Vol 11 ◽  
pp. S106-S109
Author(s):  
Tang Mei ◽  
Liu Cao ◽  
Liang Zi ◽  
Gong Mingfu ◽  
Hu Die
Keyword(s):  
High Temperature ◽  
Enzymatic Activity ◽  
Enzymatic Properties ◽  
Temperature Adaptation ◽  
Plate Method ◽  
Salting Out ◽  
Effect Of Ph ◽  
Alkaline Environment ◽  
Method Effect ◽  
Wide Range

The purpose of this study was to separate lumbrokinase in Pheretima praepinguis and examine its enzymatic properties. With P. praepinguis as material, lumbrokinase was separated with the salting out method. Lumbrokinase activity was measured with casein medium plate method. Effect of pH and temperature on lumbrokinase activity was studied. Results of lumbrokinase separated from P. praepinguis was relatively high. Lumbrokinase activity in neutral or slightly alkaline environment was higher. Lumbrokinase had tolerance ability to high temperature, with highly enzymatic activity under 60°C and wide range of temperature adaptation. 

scholarly journals The effect of ionic strength on enzymatic activity of thrombin

1990 ◽  
Vol 6 (3) ◽  
pp. 59-65 ◽  
Author(s):  
I. V. Pekhnik ◽  
M. Yu. Selishcheva ◽  
A. A. Sereyskaya
Keyword(s):  
Ionic Strength ◽  
Enzymatic Activity

Functional analysis of two isoforms of phosphatidylethanolamine N-methyltransferase

2010 ◽  
Vol 432 (2) ◽  
pp. 387-398 ◽  
Author(s):  
Shin-ya Morita ◽  
Atsuko Takeuchi ◽  
Shuji Kitagawa
Keyword(s):  
Functional Analysis ◽  
Endoplasmic Reticulum ◽  
Substrate Specificity ◽  
Enzymatic Activity ◽  
The Other ◽  
Human Embryonic Kidney ◽  
Enzymatic Assays ◽  
Hek 293 ◽  
293 Cells ◽  
High Mannose

The enzyme catalysing the conversion of PE (phosphatidylethanolamine) into PC (phosphatidylcholine), PEMT (PE N-methyltransferase), exists as two isoforms, PEMT-L (longer isoform of PEMT) and PEMT-S (shorter isoform of PEMT). In the present study, to compare the functions of the two isoforms of PEMT, we established HEK (human embryonic kidney)-293 cell lines stably expressing PEMT-L and PEMT-S. Both PEMT-L and PEMT-S were localized in the ER (endoplasmic reticulum). PEMT-L, but not PEMT-S, was N-glycosylated with high-mannose oligosaccharides. The enzymatic activity of PEMT-S was much higher than that of PEMT-L. By using novel enzymatic assays for measuring PC and PE, we showed that PEMT-L and PEMT-S expression remarkably increased the cellular PC content, whereas the PE content was decreased by PEMT-S expression, but was hardly affected by PEMT-L expression. The cellular content of phosphatidylserine was also reduced by the expression of PEMT-L or PEMT-S. MS analyses demonstrated that the expression of PEMT-S led to more increases in the molecular species of PC and PC-O (ether-linked PC) with longer polyunsaturated chains than that of PEMT-L, whereas the PC-O species with shorter chains were increased more by PEMT-L expression than by PEMT-S expression, suggesting a difference in the substrate specificity of PEMT-L and PEMT-S. On the other hand, various PE and PE-O species were decreased by PEMT-S expression. In addition, PEMT-L and PEMT-S expression promoted the proliferation of HEK-293 cells. Based upon these findings, we propose a model in which the enzymatic activity and substrate specificity are regulated by the glycosylated N-terminal region of PEMT-L localized in the ER lumen.

Some Enzymatic Properties of Trypsin after Reaction with 1-Dimethylaminonaphthalene-5-sulfonyl Chloride

1971 ◽  
Vol 49 (5) ◽  
pp. 516-521 ◽  
Author(s):  
James G. Franklin ◽  
James Leslie
Keyword(s):  
Enzymatic Activity ◽  
Ethyl Ester ◽  
Sulfonyl Chloride ◽  
Lysine Residue ◽  
Enzymatic Properties ◽  
Tyrosine Residue ◽  
General Increase ◽  
Enhanced Activity

At pH 7–8, and at 0–25°, 1-dimethylaminonaphthalene-5-sulfonyl chloride reacts with an isoleucine and a lysine residue, with some additional reaction at a tyrosine residue, in trypsin. The enzymatic activity of the modified trypsin toward N-benzoyl-DL-arginme p-nitroanilide is greater than that of the unmodified enzyme, but there is little or no change in activity toward N-benzoyl-L-arginine ethyl ester, N-benzoyl-DL-arginine ethyl ester, and N-benzoyl-L-arginine amide. The enhanced activity does not appear to be due to a general increase in the catalytic part of the mechanism of trypsin action, but rather to an increased binding of N-benzoyl-L-argimne p-nitroanilide to the enzyme.

Characterization of the enzymatic activity of human kallikrein 6: autoactivation, substrate specificity, and regulation by inhibitors

2003 ◽  
Vol 307 (4) ◽  
pp. 948-955 ◽  
Author(s):  
Angeliki Magklara ◽  
Ali A Mellati ◽  
Gregory A Wasney ◽  
Sheila P Little ◽  
Georgia Sotiropoulou ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Enzymatic Activity ◽  
Kallikrein 6

Glutamine-181 is crucial in the enzymatic activity and substrate specificity of human endoplasmic-reticulum aminopeptidase-1

2008 ◽  
Vol 416 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Yoshikuni Goto ◽  
Hiroe Tanji ◽  
Akira Hattori ◽  
Masafumi Tsujimoto
Keyword(s):  
Endoplasmic Reticulum ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Enzymatic Activity ◽  
Basic Amino Acid ◽  
Hydrolytic Activity ◽  
Site Directed Mutagenesis ◽  
Peptide Substrates ◽  
Endoplasmic Reticulum Aminopeptidase 1 ◽  
Natural Peptides

ERAP-1 (endoplasmic-reticulum aminopeptidase-1) is a multifunctional enzyme with roles in the regulation of blood pressure, angiogenesis and the presentation of antigens to MHC class I molecules. Whereas the enzyme shows restricted specificity toward synthetic substrates, its substrate specificity toward natural peptides is rather broad. Because of the pathophysiological significance of ERAP-1, it is important to elucidate the molecular basis of its enzymatic action. In the present study we used site-directed mutagenesis to identify residues affecting the substrate specificity of human ERAP-1 and identified Gln181 as important for enzymatic activity and substrate specificity. Replacement of Gln181 by aspartic acid resulted in a significant change in substrate specificity, with Q181D ERAP-1 showing a preference for basic amino acids. In addition, Q181D ERAP-1 cleaved natural peptides possessing a basic amino acid at the N-terminal end more efficiently than did the wild-type enzyme, whereas its cleavage of peptides with a non-basic amino acid was significantly reduced. Another mutant enzyme, Q181E, also revealed some preference for peptides with a basic N-terminal amino acid, although it had little hydrolytic activity toward the synthetic peptides tested. Other mutant enzymes, including Q181N and Q181A ERAP-1s, revealed little enzymatic activity toward synthetic or peptide substrates. These results indicate that Gln181 is critical for the enzymatic activity and substrate specificity of ERAP-1.

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