scholarly journals The purification and characterization of glucokinase from the thermophile Bacillus stearothermophilus

1986 ◽  
Vol 237 (2) ◽  
pp. 415-420 ◽  
Author(s):  
C R Goward ◽  
R Hartwell ◽  
T Atkinson ◽  
M D Scawen

Homogeneous glucokinase (EC 2.7.1.2) from the thermophile Bacillus stearothermophilus was isolated on the large scale by using four major steps: precipitation of extraneous material at pH 5.5, ion-exchange chromatography on DEAE-Sepharose, pseudo-affinity chromatography on Procion Brown H-3R-Sepharose 4B and gel filtration on Ultrogel AcA 34. The purified enzyme had a specific activity of about 330 units/mg of protein and was shown to exist as a dimer of subunit Mr 33,000. Kinetic parameters for the enzyme were determined with a variety of substrates. The glucokinase was highly specific for alpha-D-glucose, and the only other sugar substrate utilized was N-acetyl-alpha-D-glucosamine. The enzyme shows Michaelis-Menten kinetics, with a Km value of 150 microM for alpha-D-glucose. The glucokinase was maximally active at pH 9.0.

2013 ◽  
Vol 10 (3) ◽  
pp. 844-853
Author(s):  
Baghdad Science Journal

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.


1981 ◽  
Vol 60 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Naotika Toki ◽  
Hiroyuki Sumi ◽  
Sumiyoshi Takasugi

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.


1982 ◽  
Vol 47 (4) ◽  
pp. 1139-1148 ◽  
Author(s):  
Karel Hauzer ◽  
Linda Servítová ◽  
Tomislav Barth ◽  
Karel Jošt

Post-proline endopeptidase was isolated from pig kidneys and partially purified. The procedure consisted of fractionation with ammonium sulphate, ion exchange chromatography on DEAE-Sephadex A-50, gel filtration on Sephadex G-200 and rechromatography on DEAE-Sephadex A-50. The preparation had 55 times higher specific activity than the crude extract and did not contain any contaminating enzymic activities. The enzyme cleaved a number of proline-containing peptides and was strictly specific in catalyzing the hydrolysis of the peptide bond on the carboxyl side of the proline residue. The optimum pH for the hydrolysis of the synthetic peptides benzyl-oxycarbonylglycyl-prolyl-leucyl-glycinamide and benzyloxycarbonyl-glycyl-proline β-naphtylamide was 7.8-8.0 and, in the case of benzyloxycarbonylglycyl-proline p-nitroanilide, 7.2 to 7.5. For the hydrolysis of the tetrapeptide benzyloxycarbonylglycyl-prolyl-leucyl-glycinamide, the Km value of 75 μ mol l-1 was obtained.


2019 ◽  
Vol 6 (6) ◽  
pp. 280-286
Author(s):  
Aarthi Ravichandran ◽  
Ramya G Rao ◽  
Maheswarappa Gopinath ◽  
Manpal Sridhar

Versatile Peroxidases are high redox potential peroxidases capable of degrading lignin of lignocellulosic crop residues. Hence Versatile Peroxidases are prominent biocatalysts in upgrading lignocellulosic biomass for biotechnological applications. In the interest of exploiting the potential of Versatile Peroxidase in improving the digestibility of crop residues through delignification, a novel Versatile Peroxidase was purified and characterized from the immobilized cultures of native isolate Lentinus squarrosulus. The enzyme was purified with a specific activity of 62 U/mg through ion exchange and gel filtration chromatographic procedures. The enzyme possessed high affinity towards RB5 and manganese with a Km value of 6.84 µM for RB5 and 0.15 mM for manganese. The optimum temperature for oxidation was identified to be 30°C and optimum pH for manganese and RB5 oxidation was 5 and 3 respectively. Reactivity of the enzyme towards diverse substrates was investigated besides studying the effect of metal ions and inhibitors on RB5 oxidation. The enhanced potential of this purified Versatile Peroxidase in biodegradation of crop residues was demonstrated through augmentation of digestibility of finger millet and paddy straws by 20%.The results demonstrated that Versatile Peroxidase from Lentinus squarrosulus is capable of enhancing the nutritive value of crop residues through delignification


1986 ◽  
Vol 53 (3) ◽  
pp. 457-466 ◽  
Author(s):  
David J. Fairbairn ◽  
Barry A. Law

SUMMAEYPseudomonas fluorescensNCDO 2085 produced a single heat-stable extracellular proteinase in Na caseinate medium at 20 °C and pH 7·0. The proteinase was purified to electrophoretic homogeneity using chromatofocusing, gel filtration and ion-exchange chromatography. The purification procedure resulted in a 158-fold increase in the specific activity and a yield of 3·5% of the original activity. The enzyme is a metalloproteinase containing Zn and Ca, with an isoelectric point at 5·40±0·05 and a mol. wt of 40200±2100. It is heat-stable having D-values at 74 and 140 °C of 1·6 and 1·0 min respectively; 40 and 70% of the original activity remained after HTST (74 °C/17 s) and ultra high temperature (140°C/4 s) treatments respectively. The amino acid composition of the proteinase was determined and compared with those from otherPseudomonasspp.


2011 ◽  
Vol 7 (1) ◽  
pp. 56 ◽  
Author(s):  
Puji Lestari ◽  
Nur Richana ◽  
Abdul Aziz Darwis ◽  
Khaswar Syamsu ◽  
Untung Murdiyatmo

<p>Purification and Characterization of Thermostable<br />α-amylase from Bacillus stearothermophilus TII-12. Puji<br />Lestari, Nur Richana, Abdul A. Darwis, Khaswar Syamsu,<br />and Untung Murdiyatmo. Thermostable α-amylase is a<br />potential enzyme employed in the starch processing and<br />widely used in food industries, but this enzyme is still<br />imported. The local enzyme production would be more<br />economist and useful for its broad applications. Here we<br />report α-amylase from indigenous bacteria TII-12 which was<br />purified and characterized, as well as analyzed its hydrolysis<br />product on cassava starch. The enzyme of Bacillus<br />stearothermophilus TII-12 partially purified by ultrafiltration,<br />acetone precipitation and gel filtration (Sephadex G-100)<br />showed the reduced total activity, total protein and yield, but<br />increased the specific activity. The enzyme had a Km of 1,06<br />mg/ml and Vmax of 1,21 mol/min, with optimal activity at pH 7<br />and 90oC. An apparent molecular mass was of 192.932,8<br />Dalton, as estimated by Native-Polyacrylamide Agarose Gel<br />electrophoresis. Its activity was inhibited by the divalent<br />cation chelator such as EDTA and CuSO4 but activated by<br />calcium ion. Hydrolysis products of this enzyme on cassava<br />starch were glucose, dextrin, maltose and oligosaccharides.<br />After 24 hours of hydrolysis, the concentration of glucose<br />and maltose reached 51.970 and 10.090 ppm, respectively.<br />The thermostable α-amylase of TII-12 is an endo-α-amylase<br />and prospective to be applied on starch liquefaction with<br />high temperature process.</p>


1991 ◽  
Vol 280 (2) ◽  
pp. 341-352 ◽  
Author(s):  
N Ramasubbu ◽  
M S Reddy ◽  
E J Bergey ◽  
G G Haraszthy ◽  
S D Soni ◽  
...  

The major components of human submandibular-sublingual saliva (HSMSL) are mucins, amylases, cystatins, proline-rich proteins and statherin. Structure-function studies of these molecules have been hampered by the small amounts of purified materials that can be isolated from human secretions. The present study describes an integrated purification protocol for the large-scale preparation of many of these molecules. To dissociate partially heterotypic complexes among salivary molecules, HSMSL was initially fractionated into four pools by gel filtration with 6 M-guanidine hydrochloride. Subsequent fractionation of these four pools by gel-filtration and ion-exchange chromatography resulted in the purification of high- and low-Mr mucins, neutral and acidic cystatins, acidic and basic proline-rich proteins and statherin. Many variants or isoforms of these salivary molecules have been identified and biochemically characterized. Biochemical studies indicated that the low-Mr mucin exists as two isoforms which vary in their sialic acid to fucose ratios. Three isoforms of acidic cystatin S were characterized which differ in their phosphate content. Two isoforms of a basic proline-rich peptide were identified; the smaller peptide was a truncated form missing the first seven amino acids.


Author(s):  
Ismat Bibi ◽  
Haq Nawaz Bhatti

This study deals with purification and characterization of lignin peroxidase (LiP) isolated from Agaricus bitorqus A66 during decolorization of NOVASOL Direct Black dye. A laboratory scale experiment was conducted for maximum LiP production under optimal conditions. Purification & fractionation of LiP was performed on DEAE-Sepharose ion exchange chromatography followed by Sephadex G-50 gel filtration. The purified LiP has a specific activity of 519 U/mg with 6.73% activity recover. The optimum pH and temperature of purified LiP for the oxidation of veratryl alcohol were 6.8 and 45 °C, respectively. Michaelis-Menten kinetic constants (Vmax and Km) were determined using different concentrations of veratryl alcohol (1-35 mM). The Km and Vmax were 16.67 mM and 179.2 U/mL respectively, for veratryl alcohol oxidation as determined from the Lineweaver-Burk plot. Thermal inactivation studies were carried out at different temperatures to check the thermal stability of the enzyme. Enthalpy of activation decreased where Free energy of activation for thermal denaturation increased at higher temperatures. A possible explanation for the thermal inactivation of LiP at higher temperatures is also discussed.


2011 ◽  
Vol 63 (3) ◽  
pp. 747-756 ◽  
Author(s):  
A.K.M. Asaduzzaman ◽  
Habibur Rahman ◽  
Tanzima Yeasmin

An acid phosphatase has been isolated and purified from an extract of a germinating black gram seedling. The method was accomplished by gel filtration of a germinating black gram seedling crude extract on sephadex G-75 followed by ion exchange chromatography on DEAE cellulose. The acid phosphatase gave a single band on SDS-polyacrylamide slab gel electrophoresis. The molecular weight of the acid phosphatase determined by SDS-polyacrylamide slab gel electrophoresis was estimated to be 25 kDa. The purified enzyme showed maximum activity at pH 5 and at temperature of 55?C. Mg2+, Zn2+ and EDTA had an inhibitory effect on the activity of the acid phosphatase. Black gram seedling acid phosphatase was activated by K+, Cu2+ and Ba2+. The Km value of the enzyme was found to be 0.49 mM for pNPP as substrate.


2017 ◽  
Vol 18 (2) ◽  
pp. 1-10 ◽  
Author(s):  
Dzun Noraini Jimat ◽  
Intan Baizura Firda Mohamed ◽  
Azlin Suhaida Azmi ◽  
Parveen Jamal

A newly bacterial producing L-asparaginase was successful isolated from Sungai Klah Hot Spring, Perak, Malaysia and identified as Bacillus sp. It was the best L-asparaginase producer as compared to other isolates. Production of L-asparaginase from the microbial strain was carried out under liquid fermentation. The crude enzyme was then centrifuged and precipitated with ammonium sulfate before further purified with chromatographic method. The ion exchange chromatography HiTrap DEAE-Sepharose Fast Flow column followed by separation on Superose 12 gel filtration were used to obtain pure enzyme. The purified enzyme showed 10.11 U/mg of specific activity, 50.07% yield with 2.21 fold purification. The purified enzyme was found to be dimer in form, with a molecular weight of 65 kDa as estimated by SDS-PAGE. The maximum activity of the purified L-asparaginase was observed at pH 9 and temperature of 60°C.


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