scholarly journals Prothrombin-Sepharose-Purified Factor V and Its Role in Prothrombin Conversion

2017 ◽  
Vol 3 (1) ◽  
pp. 55-64
Author(s):  
T.C ONG

Bovine Factor V isolated by the method of Esnouf and Jobin (1967) has been further purified by affiniy chromotgraphy through prothrombin-sepharose. Factor V bound quantitative to the prothrombin-sepharose column. There was a 2-fold increase in the average specific activity (260.000 units/mg protein) of the Factor V recovered. Recovery of total Factor V activity and total protein was about 95% and 90% respectively.

1987 ◽  
Vol 262 (5) ◽  
pp. 1935-1937
Author(s):  
M.F. Lecompte ◽  
S. Krishnaswamy ◽  
K.G. Mann ◽  
M.E. Nesheim ◽  
C. Gitler

1980 ◽  
Vol 255 (2) ◽  
pp. 638-645 ◽  
Author(s):  
L.S. Hibbard ◽  
K.G. Mann

1964 ◽  
Vol 10 (1) ◽  
pp. 29-35 ◽  
Author(s):  
G. J. Stine ◽  
W. N. Strickland ◽  
R. W. Barratt

Nine methods for disrupting the mycelium of Neurospora crassa have been compared. Protein percentages are calculated per gram dry weight of mycelium. A TPN-specific glutamic acid dehydrogenase was extracted and the efficiency of each extraction method is given as total enzyme extracted and specific activity. In terms of total protein, total enzyme, and practicality of the method, the Hughes Press, the French Press and the Raper–Hyatt Press were found to be the most efficient. The advantages and limitations of each method are considered.


1970 ◽  
Vol 1 ◽  
pp. 6-10 ◽  
Author(s):  
Bidur Dhungel ◽  
Manoj Subedi ◽  
Kiran Babu Tiwari ◽  
Upendra Thapa Shrestha ◽  
Subarna Pokhrel ◽  
...  

Glucose isomerase (EC 5.3.1.5) was extracted from Streptomyces spp., isolated from Mt. Everest soil sample, and purified by ammonium sulfate fractionation and Sepharose-4B chromatography. A 7.1 fold increase in specific activity of the purified enzyme over crude was observed. Using glucose as substrate, the Michaelis constant (KM<) and maximal velocity (Vmax) were found to be 0.45M and 0.18U/mg. respectively. The optimum substrate (glucose) concentration, optimum enzyme concentration, optimum pH, optimum temperature, and optimum reaction time were 0.6M, 62.14μg/100μl, 6.9, 70ºC, and 30 minutes, respectively. Optimum concentrations of Mg2+ and Co2+ were 5mM and 0.5mM, respectively. The enzyme was thermostable with half-life 30 minutes at 100ºC.DOI: 10.3126/ijls.v1i0.2300 Int J Life Sci 1 : 6-10


2021 ◽  
Vol 12 ◽  
Author(s):  
Jing Si ◽  
Hongfei Ma ◽  
Yongjia Cao ◽  
Baokai Cui ◽  
Yucheng Dai

This study introduces a valuable laccase, designated ThLacc-S, purified from white rot fungus Trametes hirsuta. ThLacc-S is a monomeric protein in nature with a molecular weight of 57.0 kDa and can efficiently metabolize endocrine disrupting chemicals. The enzyme was successfully purified to homogeneity via three consecutive steps consisting of salt precipitation and column chromatography, resulting in a 20.76-fold increase in purity and 46.79% yield, with specific activity of 22.111 U/mg protein. ThLacc-S was deciphered as a novel member of the laccase family and is a rare metalloenzyme that contains cysteine, serine, histidine, and tyrosine residues in its catalytic site, and follows Michaelis-Menten kinetic behavior with a Km and a kcat/Km of 87.466 μM and 1.479 s–1μM–1, respectively. ThLacc-S exerted excellent thermo-alkali stability, since it was markedly active after a 2-h incubation at temperatures ranging from 20 to 70°C and retained more than 50% of its activity after incubation for 72 h in a broad pH range of 5.0–10.0. Enzymatic activities of ThLacc-S were enhanced and preserved when exposed to metallic ions, surfactants, and organic solvents, rendering this novel enzyme of interest as a green catalyst for versatile biotechnological and industrial applications that require these singularities of laccases, particularly biodegradation and bioremediation of environmental pollutants.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Imen Lahmar ◽  
Hanen El Abed ◽  
Bassem Khemakhem ◽  
Hafedh Belghith ◽  
Ferjani Ben Abdallah ◽  
...  

A continuous research is attempted to fulfil the highest industrial demands of natural amylases presenting special properties. Newα-amylases extracted from stems and leaves ofPergularia tomentosa, which is widespread and growing spontaneously in Tunisia, were studied by the means of their activities optimization and purification. Some similarities were recorded for the two identified enzymes: (i) the highest amylase activity showed a promoted thermal stability at 50°C; (ii) the starch substrate at 1% enhanced the enzyme activity; (iii) the twoα-amylases seem to be calcium-independent; (iv) Zn2+, Cu2+, and Ag2+were considered as important inhibitors of the enzyme activity. Following the increased gradient of elution on Mono Q-Sepharose column, an increase in the specific activity of 11.82-fold and 10.92-fold was recorded, respectively, for leaves and stems with the presence of different peaks on the purification profiles.Pergulariaamylases activities were stable and compatible with the tested commercial detergents. The combination of plant amylase and detergent allowed us to enhance the wash performance with an increase of 35.24 and 42.56%, respectively, for stems and leaves amylases. Characterized amylases were reported to have a promoted potential for their implication notably in detergent industry as well as biotechnological sector.


2021 ◽  
Vol 30 (1) ◽  
pp. 102-109
Author(s):  
Dhananjay Mishra ◽  
K.Venu Achari

We determined the kinetics of metamorphosis, apoptosis, and tail regression in Rana tigrina. Acid phosphatase activity (µMole Pi.hr-1.tail-1) in the growing and regressing tail attended six to thirty fold increase respectively. However total activity in the trunk was decreased through progressive growing stages of metamorphosis. Total protein content in the trunk of tadpoles at climax stage (XXI) was decrease (35%) from 2.6mg/ml to 1.7mg/ml. The tail of tadpole tissue has shown a two fold increase in total Ribonucleic Acid (RNA) content from stage III to stage XVIII. But there was again decrease in total RNA content at climax stage (stage XXI). This might be possible due to decreased protein synthetic status. When the experiment was performed in trunk homogenate the amount of total carbohydrate (mg/ml) was slightly increased from 37mg/ml to 38.6mg/ml. this might be due to increase in the activity of α-amylase enzymes in the viscera of developing tadpole when it reached the climax stage.


1989 ◽  
Vol 257 (4) ◽  
pp. G616-G623 ◽  
Author(s):  
H. A. Buller ◽  
A. G. Van Wassenaer ◽  
S. Raghavan ◽  
R. K. Montgomery ◽  
M. A. Sybicki ◽  
...  

Lactase-phlorizin hydrolase, a small intestinal disaccharidase, has been considered mainly an enzyme important only for the hydrolysis of lactose. After weaning in most mammals lactase-specific activity falls markedly, and, functionally, adult mammals are considered to be lactase deficient. However, the persistence of low levels of lactase activity in adulthood has never been explained. In addition, it has been suggested that lactase-phlorizin hydrolase is associated with glycosylceramidase activity when the enzyme is prepared by column chromatography, but it is unclear whether this represents copurified activities or two catalytic sites on one peptide. The developmental patterns of lactase-phlorizin hydrolase and other disaccharidases were investigated in homogenates of total rat small intestine; lactase and several glycosylceramidases were measured in immunoprecipitates from these homogenates using a monoclonal antibody. The developmental pattern of total lactase activity showed a steady 2.3-fold increase to adult levels (specific activity decreased eightfold), whereas total phlorizin-hydrolase activity increased 10.7-fold (specific activity decreased threefold). As expected, levels of both total and specific sucrase and maltase activities increased during development. In lactating rats total lactase activity showed a significant increase compared with adult males. The developmental pattern of the enzyme activities for the glycolipid substrates was similar to that found for lactase, and the immunoprecipitated enzyme showed a 40- to 55-fold higher affinity for the glycolipids than for lactose. Galactosyl- and lactosylceramide inhibited lactose hydrolysis by 38%, without a competitive pattern, suggesting two different active sites for lactose and glycolipid hydrolysis, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)


Blood ◽  
1990 ◽  
Vol 76 (10) ◽  
pp. 2011-2016 ◽  
Author(s):  
JL Zehnder ◽  
LL Leung

Abstract A 65 year old patient who was exposed to topical bovine thrombin during cardiac surgery developed markedly prolonged clotting times and a severe bleeding diathesis. Mixing studies with normal plasma failed to correct the clotting times. Platelet transfusions, immunosuppressive and immunomodulatory therapies were ineffective, but plasmapheresis was effective in decreasing clotting times and in the resolution of clinical bleeding events. The patient's purified IgG reacted with bovine thrombin by immunoblotting and enzyme-linked immunosorbent assay (ELISA). However, the IgG reacted minimally with human thrombin. In view of the severe bleeding, a coexisting inhibitor was sought. The patient's factor V activity was 1% of normal and was not corrected by mixing with normal plasma, demonstrating the presence of an inhibitor against factor V. The patient's IgG reacted with both bovine and human factor V. Immunoblotting localized the site of antibody binding to the light chain of activated bovine factor V. Detectable amounts of bovine factor V were found in commercial bovine thrombin preparations by ELISA. The data suggest that patients exposed to topical bovine thrombin may develop antibodies to thrombin and factor V. Anti-thrombin antibodies may mask coexisting factor V inhibitors responsible for clinical bleeding.


1975 ◽  
Vol 2 (2) ◽  
pp. 129
Author(s):  
M.E Gordon ◽  
D.S Letham

The cytokinin 6-benzylaminopurine (BAP) markedly stimulated the lateral expansion of excised immature radish cotyledons after a lag period of about 10 h. This growth occurred principally by cell enlargement, especially in the light which enhanced the response. However, a marked response 'to cytokinin occurred in the complete absence of red light during germination, cotyledon excision and incubation. Contact with BAP for 5 h significantly stimulated growth, but a maximum response required more than 24 h of contact; potassium chloride also promoted cotyledon expansion and acted synergistically with cytokinin. The response to cytokinin did not appear to be mediated by ethylene, gibberellins, polyamines or cyclic nucleotides. Growth induction did not alter the respiration rate and appeared to be inde- pendent of chloroplast function. Inhibitors of DNA and RNA synthesis and of protein synthesis on cytoplasmic ribosomes almost completely abolished BAP-induced growth, control growth being less markedly affected. There were, however, no significant BAP-induced increases in total DNA or RNA levels or specific activity before the initiation of growth stimulation. Similarly, BAP had no effect on any individual RNA species until after the lag period, when there was a small enhancement of uridine incorporation into RNA species with similar electrophoretic mobility to rRNA. Although total protein levels were not affected by BAP, the cytokinin enhanced amino acid incorporation into protein within the lag period, an effect which persisted when transcription was strongly inhibited by actinomycin D. Phosphorylation of total protein was stimulated by BAP only well after the onset of cytokinin-induced growth. Protein methylation, however, was stimulated by BAP during the lag period, and the effect was at least as early as the BAP-enhanced incorporation of methionine into protein. The possible role of translational control in the mechanism of cytokinin action is discussed.


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