scholarly journals LccA, an Archaeal Laccase Secreted as a Highly Stable Glycoprotein into the Extracellular Medium by Haloferax volcanii

2009 ◽  
Vol 76 (3) ◽  
pp. 733-743 ◽  
Author(s):  
Sivakumar Uthandi ◽  
Boutaiba Saad ◽  
Matthew A. Humbard ◽  
Julie A. Maupin-Furlow
Keyword(s):  
Culture Supernatant ◽  
Specific Activity ◽  
Haloferax Volcanii ◽  
Organic Substrates ◽  
Amino Acid Residues ◽  
Multicopper Oxidases ◽  
Absorbance Spectrum ◽  
Purification And Characterization ◽  
Extracellular Medium

ABSTRACT Laccases couple the oxidation of phenolic compounds to the reduction of molecular oxygen and thus span a wide variety of applications. While laccases of eukaryotes and bacteria are well characterized, these enzymes have not been described in archaea. Here, we report the purification and characterization of a laccase (LccA) from the halophilic archaeon Haloferax volcanii. LccA was secreted at high levels into the culture supernatant of a recombinant H. volcanii strain, with peak activity (170 ± 10 mU·ml− 1) at stationary phase (72 to 80 h). LccA was purified 13-fold to an overall yield of 72% and a specific activity of 29.4 U·mg− 1 with an absorbance spectrum typical of blue multicopper oxidases. The mature LccA was processed to expose an N-terminal Ala after the removal of 31 amino acid residues and was glycosylated to 6.9% carbohydrate content. Purified LccA oxidized a variety of organic substrates, including bilirubin, syringaldazine (SGZ), 2,2,-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and dimethoxyphenol (DMP), with DMP oxidation requiring the addition of CuSO4. Optimal oxidation of ABTS and SGZ was at 45°C and pH 6 and pH 8.4, respectively. The apparent K m values for SGZ, bilirubin, and ABTS were 35, 236, and 670 μM, with corresponding k cat values of 22, 29, and 10 s− 1, respectively. The purified LccA was tolerant of high salt, mixed organosolvents, and high temperatures, with a half-life of inactivation at 50°C of 31.5 h.

Purification and characterization of two isoforms of native α amylase from Ok-Rong mango (Mangifera indica Linn. cv. Ok-Rong)

2017 ◽  
Vol 42 (6) ◽  
Author(s):  
Raksmont Ubonbal ◽  
Saijai Porsoongnoen ◽  
Jureerut Daduang ◽  
Sompong Klaynongsruang ◽  
Sakda Daduang
Keyword(s):  
High Temperatures ◽  
Fruit Ripening ◽  
Specific Activity ◽  
Mangifera Indica ◽  
Ripening Stage ◽  
Purification And Characterization ◽  
Tropical Plant ◽  
Short Period ◽  
Structure Properties

AbstractIntroduction:The tropical plant amylases involved in the fruit ripening stage is outstanding for their high activities in converting starch to sugars within a short period at high temperatures over 40°C.Methods:The α amylase iso-enzymes from Ok-Rong mango (Results:The enzyme was purified 105-fold with a final specific activity of 59.27 U mgConclusion:Two α amylase iso-enzymes were classified as members of the low-pI group of amylases with identical structure, properties and functions. They are mesophilic with high possibilities for application for many purposes.

Screening and characterization of thermostable fibrinolytic enzyme from Bacillus amyloliquefaciens EGE-B-2d.1 / Bacillus amyloliquefaciens EGE-B-2d.1’den termostabil fibrinolitik enzimin taranması ve karakterizasyonu

2016 ◽  
Vol 41 (3) ◽  
Author(s):  
Birkan Slem ◽  
Yüksel Gezgin ◽  
Rengin Eltem
Keyword(s):  
Bacillus Amyloliquefaciens ◽  
Fibrinolytic Activity ◽  
Culture Supernatant ◽  
Specific Activity ◽  
Fibrinolytic Therapy ◽  
Fibrinolytic Enzyme ◽  
Fibrinolytic Enzymes ◽  
Enzyme Thermostability ◽  
Natural Agent

AbstractObjective: To screen fibrinolytic enzyme-producing Bacillus isolates (n=210) and to characterize of thermostable fibrinolytic enzyme from Bacillus amyloliquefaciens EGE-B-2d.1 that had the highest level of fibrinolytic activity together with the highest thermostability.Methods: Firstly, a total of 210 isolates were screened for their fibrinolytic enzyme production. The potent fibrinolytic enzyme producing isolates were evaluated for the thermostability of their fibrinolytic enzymes and one isolate showing prominent fibrinolytic activity was identified as molecular. Fermentation process was carried out on the isolate that had both the highest level of fibrinolytic activity and enzyme thermostability. The thermostable fibrinolytic enzyme from this isolate was then purified and characterized.Results: The fibrinolytic enzyme activities of 21 Bacillus sp. isolates in Nutrient Yeast Salt Medium were found to be in the range of 0.176-1.734 U/ml. The fibrinolytic activity of the enzyme purified from the culture supernatant of Bacillus amyloliquefaciens EGE-B-2d.1 was relatively stable at pH 7.0-11.0 for 24 h and also showed stability at a temperature of 60°C for 60 min. The enzyme degraded the fibrin clots by direct fibrinolysis. The specific activity and the molecular weight of the purified enzyme were estimated to be 44.46 units/mg protein and 30 kD respectively.Conclusion: The thermostable fibrinolytic enzyme from Bacillus amyloliquefaciens EGE-B-2d.1 was purified and characterized. This enzyme might also be used as a natural agent for oral fibrinolytic therapy or thrombosis prevention.

scholarly journals Purification and Characterization of Endoglucanase from local isolate of Aspergillus flavus

2013 ◽  
Vol 10 (3) ◽  
pp. 844-853
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aspergillus Flavus ◽  
Specific Activity ◽  
Gel Filtration ◽  
Temperature Stability ◽  
Exchange Chromatography ◽  
Purification And Characterization ◽  
Original Activity ◽  
A Value ◽  
Optimum Ph

Endoglucanase produced from Aspergillus flavus was purified by several steps including precipitation with 25 % ammonium sulphate followed by Ion –exchange chromatography, the obtained specific activity was 377.35 U/ mg protein, with a yield of 51.32 % .This step was followed by gel filtration chromatography (Sepharose -6B), when a value of specific activity was 400 U/ mg protein, with a yield of 48 %. Certain properties of this purified enzyme were investigated, the optimum pH of activity was 7 and the pH of its stability was 4.5, while the temperature stability was 40 °C for 60 min. The enzyme retained 100% of its original activity after incubation at 40 °C for 60 min; the optimum temperature for enzyme activity was 40 °C.

Gene Cloning, Nucleotide Sequencing, and Purification and Characterization of the Low-Specificityl-Threonine Aldolase from Pseudomonas sp. Strain NCIMB 10558

1998 ◽  
Vol 64 (2) ◽  
pp. 549-554 ◽  
Author(s):  
Ji-Quan Liu ◽  
Saeko Ito ◽  
Tohru Dairi ◽  
Nobuya Itoh ◽  
Michihiko Kataoka ◽  
...  
Keyword(s):  
Amino Acid ◽  
Significant Loss ◽  
Site Directed Mutagenesis ◽  
Nucleotide Sequencing ◽  
Predicted Amino Acid Sequence ◽  
Amino Acid Residues ◽  
Purification And Characterization ◽  
Reading Frame ◽  
Threonine Aldolase

ABSTRACT A low-specificity l-threonine aldolase (l-TA) gene from Pseudomonas sp. strain NCIMB 10558 was cloned and sequenced. The gene contains an open reading frame consisting of 1,041 nucleotides corresponding to 346 amino acid residues. The gene was overexpressed in Escherichia colicells, and the recombinant enzyme was purified and characterized. The enzyme, requiring pyridoxal 5′-phosphate as a coenzyme, is strictlyl specific at the α position, whereas it cannot distinguish between threo and erythro forms at the β position. In addition to threonine, the enzyme also acts on various other l-β-hydroxy-α-amino acids, includingl-β-3,4-dihydroxyphenylserine,l-β-3,4-methylenedioxyphenylserine, andl-β-phenylserine. The predicted amino acid sequence displayed less than 20% identity with those of low-specificityl-TA from Saccharomyces cerevisiae,l-allo-threonine aldolase from Aeromonas jandaei, and four relevant hypothetical proteins from other microorganisms. However, lysine 207 of low-specificity l-TA from Pseudomonas sp. strain NCIMB 10558 was found to be completely conserved in these proteins. Site-directed mutagenesis experiments showed that substitution of Lys207 with Ala or Arg resulted in a significant loss of enzyme activity, with the corresponding disappearance of the absorption maximum at 420 nm. Thus, Lys207 of thel-TA probably functions as an essential catalytic residue, forming an internal Schiff base with the pyridoxal 5′-phosphate of the enzyme to catalyze the reversible aldol reaction.

Characterization of a Bacteriocin Produced by Enterococcus faecalis N1-33 and Its Application as a Food Preservative

2009 ◽  
Vol 72 (3) ◽  
pp. 524-530 ◽  
Author(s):  
TOMOMI HATA ◽  
MELAKU ALEMU ◽  
MIHO KOBAYASHI ◽  
CHISE SUZUKI ◽  
SUNEE NITISINPRASERT ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Marked Reduction ◽  
Pathogenic Bacteria ◽  
Culture Supernatant ◽  
Amino Acid Residues ◽  
Bacteriocin Activity ◽  
Food Preservative ◽  
Fermented Bamboo Shoot ◽  
Potential Use

A bacteriocin-producing strain, N1-33, isolated from fermented bamboo shoot was identified as Enterococcus faecalis. The pH-adjusted culture supernatant of this strain consisted of several peptides with bacteriocin activity, and the supernatant inhibited the growth of pathogenic bacteria such as Listeria monocytogenes. The major peptide with bacteriocin activity was purified, and the first 39 amino acid residues of the bacteriocin were found to be identical to enterocin MR10A produced by E. faecalis MRR10-3. Addition of the pH-adjusted and concentrated culture supernatant of strain N1-33 caused a marked reduction in the growth of Bacillus cereus in custard cream and L. monocytogenes in pickled cucumber. These results suggest the potential use of the bacteriocin produced by strain N1-33 in food biopreservation.

scholarly journals Partial purification and characterization of human erythrocyte phosphoglycollate phosphatase

1980 ◽  
Vol 191 (1) ◽  
pp. 117-124 ◽  
Author(s):  
R Zecher ◽  
H U Wolf
Keyword(s):  
Specific Activity ◽  
Total Activity ◽  
Partial Purification ◽  
Half Maximum ◽  
Purification And Characterization ◽  
Dimeric Molecule ◽  
Maximum Inhibition ◽  
Optimum Ph ◽  
Triton X

Human erythrocytes contain a phosphatase that is highly specific for phosphoglycollate. It shows optimum pH of 6.7 and has Km 1 mM for phosphoglycollate. The molecular weight appears to be about 72000. The enzyme is a dimeric molecule having subunits of mol. wt. about 35000. It could be purified approx. 4000-fold up to a specific activity of 5.98 units/mg of protein. The activity of the enzyme is Mg2+-dependent. Co2+, and to a smaller extent Mn2+, may substitute for Mg2+. Half-maximum inhibition of the phosphatase by 5,5′-dithiobis-(2-nitrobenzoate), EDTA and NaF is obtained at 0.5 microM, 1 mM and 4 mM respectively. Moreover, it needs a univalent cation for optimum activity. Phosphoglycollate phosphatase is a cytoplasmic enzyme. Approx. 5% of its total activity is membrane-associated. This part of activity can be approx. 70% solubilized by freezing, thawing and treatment with 0.25% Triton X-100.

scholarly journals Purification and characterization of 3-dehydroquinase from Escherichia coli

1986 ◽  
Vol 239 (3) ◽  
pp. 699-704 ◽  
Author(s):  
S Chaudhuri ◽  
J M Lambert ◽  
L A McColl ◽  
J R Coggins
Keyword(s):  
Escherichia Coli ◽  
Gel Electrophoresis ◽  
Catalytic Properties ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Permeation Chromatography ◽  
Purification And Characterization ◽  
Gel Permeation

A procedure has been developed for the purification of 3-dehydroquinase from Escherichia coli. Homogeneous enzyme with specific activity 163 units/mg of protein was obtained in 19% overall yield. The subunit Mr estimated from polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate was 29,000. The native Mr, estimated by gel permeation chromatography on Sephacryl S-200 (superfine) and on TSK G3000SW, was in the range 52,000-58,000, indicating that the enzyme is dimeric. The catalytic properties of the enzyme have been determined and shown to be very similar to those of the biosynthetic 3-dehydroquinase component of the arom multifunctional enzyme of Neurospora crassa.

Purification and Characterization of Kallikrein from Plasma of Patients with Acute Pancreatitis

1981 ◽  
Vol 60 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Naotika Toki ◽  
Hiroyuki Sumi ◽  
Sumiyoshi Takasugi
Keyword(s):  
Acute Pancreatitis ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Apparent Molecular Weight ◽  
Purification And Characterization ◽  
Α2 Macroglobulin ◽  
Sepharose 4B

1. A kallikrein-like enzyme in plasma of patients with acute pancreatitis was further purified by successive hydroxyapatite/cellulose and Sepharose-4B column chromatography. 2. By these procedures 0.26 mg of purified enzyme with a specific activity of 215 S-2266 chromozyme units/mg of protein was obtained from 10 ml of original plasma. 3. The purified material was homogeneous as ascertained by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and had an apparent molecular weight of 31 000 as measured by gel filtration on Sephadex G-200. 4. It was confirmed immunologically that this enzyme was pancreatic kallikrein, which is distinct from plasma kallikrein, and that it could combine with α2-macroglobulin only in the presence of trypsin.

scholarly journals New de-ubiquitinating enzyme, ubiquitin C-terminal hydrolase 8, in chick skeletal muscle

1997 ◽  
Vol 325 (2) ◽  
pp. 325-330 ◽  
Author(s):  
Sung Hee BAEK ◽  
Seung Kyoon WOO ◽  
Jae LEE ◽  
Yung Joon YOO ◽  
Choong Myung CHO ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Amino Acid Residues ◽  
Purification And Characterization ◽  
Ubiquitinated Protein ◽  
Protein Conjugates ◽  
Isopeptide Bonds ◽  
Linear Poly ◽  
Single Polypeptide ◽  
Free Ubiquitin

We have previously shown that chick muscle extracts contained at least 10 different ubiquitin C-terminal hydrolases (UCHs). Here we report the purification and characterization of one of the UCHs, called UCH-8, with 125I-labelled ubiquitin-α-NH-MHISPPEPESEEEEEHYC as a substrate. The purified UCH-8 behaved as a 240 kDa protein on a Superdex-200 column under non-denaturing conditions but as a 130 kDa polypeptide on analysis by PAGE under denaturing conditions, suggesting that the enzyme consists of two identical subunits. Thus this enzyme seems to be distinct in its dimeric nature from other purified UCHs that consist of a single polypeptide, except that UCH-6 is also a homodimer of 27 kDa subunits. UCH-8 was maximally active between pH 7.5 and 8, but showed little or no activity below pH 7 and above pH 9. Like other UCHs it was sensitive to inhibition by thiol-blocking agents such as N-ethylmaleimide, and by ubiquitin aldehyde. The purified UCH-8 hydrolysed not only ubiquitin-α-NH-protein extensions, including ubiquitin-α-NH-carboxy extension protein of 80 amino acid residues and ubiquitin-α-NH-dihydrofolate reductase, but also branched poly-ubiquitin that are ligated to proteins through ϵ-NH-isopeptide bonds. However, it showed little or no activity against poly-His-tagged di-ubiquitin, suggesting that UCH-8 is not involved in the generation of free ubiquitin from the linear poly-ubiquitin precursors. These results suggest that UCH-8 might have an important role in the production of free ubiquitin and ribosomal proteins from their conjugates as well as in the recycling of ubiquitin molecules after the degradation of poly-ubiquitinated protein conjugates by the 26 S proteasome.

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