scholarly journals Decolourisation of Reactive Black 5 by Azoreductase Produced by Brevibacillus panacihumi ZBI

2012 ◽  
Vol 59 (1) ◽  
Author(s):  
Masyithah Aalia Mohd Ramlan ◽  
Nadhirah Aminah Azizan ◽  
Bay Hui Han ◽  
Lim Chi Kim ◽  
Shaza Eva Mohamad ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Enzyme Activity ◽  
Phosphate Buffer ◽  
Culture Supernatant ◽  
Specific Activity ◽  
Enzyme Reaction ◽  
Reactive Black 5 ◽  
Degrading Bacterium ◽  
The Stability ◽  
Assay Conditions

Azoreductases are often associated with decolourisation of non–degradable azo dyes via cleavage of azo bonds. In this study,Brevibacillus panacihumi ZBI, an azo dye–degrading bacterium which has not been reported before, was used for the decolourisation of Reactive Black 5 (RB5) dye. The highest activity of azoreductase was obtained during the end of log phase. Azoreductase produced intracellularly had the highest specific activity of 0.334 U/mg compared to the culture supernatant (extracellular), resting cell and cell debris with low enzyme activity of 0.034 U/mg, 0.010 U/mg and 0.200 U/mg respectively. The optimum assay conditions for the maximum azoreductase activity were at 37°C, pH 7, RB5 dye concentration of 100 mg/L and NADH concentration of 0.2 mM by using phosphate buffer as a medium for the enzyme reaction. Alternatively, the azoreductase assay was also carried out using ionic liquid, [emim][EtSO4] that may function to enhance the activity and stability of azoreductase. Results using phosphate buffer (pH 7) showed higher enzyme activity twice that of the ionic liquid besides enhancing the stability of enzyme. Under the optimum assay conditions up to 93 % of decolourisation was achieved after 8 h of incubation. In addition, growth of bacteria was also concurrently observed during the decolourisation of RB5.

scholarly journals EFFECT OF USING L-ASPARAGINASE IN REDUCING ACRYLAMIDE PERCENTAGE IN BISICUT

2016 ◽  
Vol 47 (4) ◽  
Author(s):  
Jebur & et al.
Keyword(s):  
High Performance Liquid Chromatography ◽  
Enzyme Activity ◽  
Liquid Chromatography ◽  
High Performance ◽  
Specific Activity ◽  
Control Sample ◽  
The Other ◽  
Enzyme Efficiency ◽  
Negative Effect ◽  
The Stability

This study was aimed to know the efficiency of partially purified L- asparaginase produced from local isolate from Erwinia spp. to reduce the percentage of acrylamide formed in Biscuit. Four types of biscuit from wheat flour were prepared (T1, T2, T3, T4),and T1 as control. High performance liquid chromatography technique was used to estimate acrylamide ratio in biscuit , Effect of enzyme addition  on flour chemical and rheological properties was studied, also dough behavior ,gluten percentage, water absorption and amylase enzyme activity was estimated. The results revealed  that  the  addition of  experimental asparaginase ( specific activity 20.5 unite mg-1 ) with 1% of flour weight lead to reduce in acrylamide formation in Biscuit  to 89 %  compared  to  control sample ( in absence of enzyme ) . Moreover, the addition of Asparagine to flour at 0.1 % of its weight, where L- asparaginase was available caused a negative effect on enzyme efficiency in reducing the acrylamide in biscuit. So the level of acrylamide was reduced to 57.7 %. In the other hand , the percentage of acryl amide in biscuit was increased to   233 % when the asparagine was added to mixture in absence of L- asparaginase .Addition of  the enzyme to flour have no effect on the percentage value of gluten but improved the  stability of dough .The  enzyme  addition also led to increase amylases activities.  Addition of experimental enzyme had no effect on quality and sensory evaluation of biscuit.

scholarly journals A Discussion of Enzyme Reference Materials: Applications and Specifications

1973 ◽  
Vol 19 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Charles F Fasce ◽  
Robert Rej ◽  
William H Copeland ◽  
Raymond E Vanderlinde
Keyword(s):  
Enzyme Activity ◽  
Reference Materials ◽  
Aspartate Aminotransferase ◽  
Specific Activity ◽  
High Specific Activity ◽  
Aminotransferase Activity ◽  
Precision Control ◽  
Clinical Laboratories ◽  
Assay Conditions

Abstract Clinical laboratories estimating enzyme activity in serum are using commercial lyophilized sera for four major purposes. These uses—as a standard and for intermethod, intramethod, and precision control—are segregated, and specifications for each deployment are examined in terms of requirements for the enzyme material: freedom from interfering or indicator enzymes and chromogens; high specific activity; inclusion of optimal cofactor concentrations; commutability, human properties and source; the presence of a single isoenzyme; and stability. The effects of serum matrix and variable assay conditions on the utility of enzyme materials are analyzed. Specifications differ for each enzyme material application. The compatibility of commercial lyophilized sera containing aspartate aminotransferase activity with several cited specifications is assessed

scholarly journals Dihydro-orotase from Clostridium oroticum. Purification and reversible removal of essential zinc

1985 ◽  
Vol 230 (1) ◽  
pp. 101-108 ◽  
Author(s):  
D W Pettigrew ◽  
R R Bidigare ◽  
B J Mehta ◽  
M I Williams ◽  
E G Sander
Keyword(s):  
Enzyme Activity ◽  
Amino Acid ◽  
Phosphate Buffer ◽  
Specific Activity ◽  
Zinc Content ◽  
Atomic Absorption Spectrophotometry ◽  
Kinetic Properties ◽  
Purification Procedure ◽  
Normal Complement ◽  
Absorption Spectrophotometry

A new purification procedure involving five column-chromatography steps is described for dihydro-orotase (L-5,6-dihydro-orotate amidohydrolase, EC 3.5.2.3) from Clostridium oroticum (A.T.C.C. 25750). The native purified enzyme is a dimer of Mr 102 000 and contains 4.0 +/- 0.3 g-atoms of zinc/mol of dimer. These observations agree with those reported previously [Taylor, Taylor, Balch & Gilchrist (1976) J. Bacteriol. 127, 863-873]. It is conclusively demonstrated that dihydro-orotase is a zinc metalloenzyme. Zinc is reversibly removed by treatment with chelators in phosphate buffer at pH 6.5, as demonstrated by atomic absorption spectrophotometry and decrease of enzyme activity. The specific activity is linearly dependent on zinc content. Addition of ZnSO4 to the chelator-treated enzyme results in regain of the normal complement of zinc and enzyme activity. Kinetic properties of the reconstituted enzyme are indistinguishable from those of the native enzyme. The amino acid composition of the homogeneous enzyme suggests that the zinc atoms occupy different environments.

Purification and some characteristics of a Ca2+-activated proteolytic enzyme from beef cardiac muscle

1981 ◽  
Vol 59 (4) ◽  
pp. 242-249 ◽  
Author(s):  
Susan Tolnai
Keyword(s):  
Enzyme Activity ◽  
Cardiac Muscle ◽  
Specific Activity ◽  
Fold Increase ◽  
Fresh Tissue ◽  
Total Enzyme Activity ◽  
Calcium Dependent ◽  
And Storage ◽  
Assay Conditions ◽  
Salt Fractionation

A calcium-dependent neutral proteinase was purified from beef cardiac muscle. The crude extract prepared from cardiac muscle was subjected to acid precipitation and salt fractionation and then further purified by column chromatography on Sepharose 6B, DE-52, and Sephadex G-200 columns in succession. The final preparation showed an 11 300 fold increase in specific activity of the Ca2+-activated enzyme. Average enzyme protein yield was 2.4 μg/g fresh tissue. The enzyme was maximally active at pH 7.6 in the presence of 4 mM calcium. Proportionality of enzyme activity in partially purified preparations was retained when activity was measured at 25 °C using casein as the substrate. The rate of proteolysis by the purified enzyme was linear for 60 min under similar assay conditions. Fractionation of muscle homogenates showed that 70 to 73% of the total enzyme activity was present in the 24 000 × g and 30 000 × g supernatants. The enzyme was labile in aqueous solutions and storage at 4 °C and −20 °C resulted in considerable loss of activity, unless glycerol (50% v/v) was added to the solution.

scholarly journals Purification and characterization of an acetyl xylan esterase produced by Streptomyces lividans

1996 ◽  
Vol 319 (3) ◽  
pp. 881-886 ◽  
Author(s):  
Claude DUPONT ◽  
Nicole DAIGNEAULT ◽  
François SHARECK ◽  
Rolf MOROSOLI ◽  
Dieter KLUEPFEL
Keyword(s):  
Enzyme Activity ◽  
Culture Filtrate ◽  
Specific Activity ◽  
Streptomyces Lividans ◽  
Birchwood Xylan ◽  
Acetyl Xylan Esterase ◽  
Purification And Characterization ◽  
Acetyl Group ◽  
Assay Conditions

The acetyl xylan esterase cloned homologously from Streptomyces lividans [Shareck, Biely, Morosoli and Kluepfel (1995) Gene 153, 105–109] was purified from culture filtrate of the overproducing strain S. lividans IAF43. The secreted enzyme had a molecular mass of 34 kDa and a pI of 9.0. Under the assay conditions with chemically acetylated birchwood xylan the kinetic constants of the enzyme were: specific activity, 715 units/mg, Km 7.94 mg/ml and Vmax 1977 units/mg. Optimal enzyme activity was obtained at 70 °C and pH 7.5. Hydrolysis assays with different acetylated substrates showed that the enzyme is specific for deacetylating the O-acetyl group of polysaccharides and is devoid of N-deacetylation activity. Sequential hydrolysis shows that its action is essential for the complete degradation of acetylated xylan by the xylanases of S. lividans.

scholarly journals Mechanical and Electrical Performance of Flexible Polymer Film Designed for a Textile Electrically-Conductive Path

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2169
Author(s):  
Agnieszka Tabaczyńska ◽  
Anna Dąbrowska ◽  
Marcin Masłowski ◽  
Anna Strąkowska
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Surface Resistance ◽  
Conductive Filler ◽  
Extrusion Process ◽  
Electrical Performance ◽  
Electrically Conductive ◽  
Non Invasive ◽  
Flexible Polymer ◽  
The Stability

Electro-conductive paths that are mechanically resistant and stable during simulated aging cycles are promising, in relation to the non-invasive application in e-textiles in our everyday surroundings. In the paper, an analysis of the influence of electro-conductive filler, as well as ionic liquid on surface resistance is provided. Authors proved that depending on the tested variant, obtained surface resistance may vary from 50 kΩ (when 50 phr of Ag and [bmim][PF6] ionic liquid applied) to 26 GΩ (when 25 phr of Ag and [bmim][PF6] ionic liquid applied). The samples were also evaluated after simulated aging cycles and the stability of electric properties was confirmed. Moreover, it was proved that the addition of ionic liquids reduced the resistance of vulcanizates, while no significant influence of the extrusion process on conductivity was observed.

Serum Cholinesterase Variants: Examination of Several Differential Inhibitors, Salts, and Buffers Used to Measure Enzyme Activity

1971 ◽  
Vol 17 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Philip J Garry
Keyword(s):  
Enzyme Activity ◽  
Sodium Fluoride ◽  
Phosphate Buffer ◽  
Divalent Cations ◽  
Kinetic Studies ◽  
Competitive Inhibitor ◽  
Serum Cholinesterase ◽  
Low Concentrations

Abstract Dibucaine, used as a differential inhibitor with acetyl-, propionyl-, and butyrylthiocholine as substrate, clearly identified the "usual" and "atypical" serum cholinesterases. Succinylcholine was also used successfully as a differential inhibitor with butyrylthiocholine as substrate. Sodium fluoride, used as a differential inhibitor, gave conflicting results, depending on whether Tris or phosphate buffer was used in the assay. Mono- and divalent cations (NaCl, KCl, MgCl2, CaCl2, and BaCl2) activated the "usual" and inhibited the "atypical" enzyme at low concentrations. The "usual" enzyme had the same activity in 0.05 mol of Tris or phosphate buffer per liter, while the heterozygous and "atypical" enzymes showed 12 and 42% inhibition, respectively, when assayed in the phosphate buffer. Kinetic studies showed the phosphate acted as a competitive inhibitor of "atypical" enzyme. Km values, determined for "usual" and "atypical" enzymes, were 0.057 and 0.226 mmol/liter, respectively, with butyrylthiocholine as substrate.

scholarly journals Study of Extraction and Enzymatic Properties of Cell-Envelope Proteinases from a Novel Wild Lactobacillus plantarum LP69

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 325 ◽  
Author(s):  
He Chen ◽  
Jie Huang ◽  
Binyun Cao ◽  
Li Chen ◽  
Na Song ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Lactobacillus Plantarum ◽  
Industrial Development ◽  
Extraction Efficiency ◽  
Specific Activity ◽  
Cell Envelope ◽  
Serine Proteinase ◽  
Kinetic Studies ◽  
Predicted Values ◽  
Hydrolyze Whey Protein

Lactobacilli cell-envelope proteinases (CEPs) have been widely used in the development of new streams of blockbuster nutraceuticals because of numerous biopharmaceutical potentials; thus, the development of viable methods for CEP extraction and the improvement of extraction efficiency will promote their full-scale application. In this study, CEP from a novel wild Lactobacillus plantarum LP69 was released from cells by incubating in calcium-free buffer. The extraction conditions of CEP were optimized by response surface methodology with the enzyme activity and specific activity as the detective marker. The optimal extraction conditions were: time of 80 min, temperature of 39 °C and buffer pH of 6.5. Under these conditions, enzyme activity and specific activity were (23.94 ± 0.86) U/mL and (1.37 ± 0.03) U/mg, respectively, which were well matched with the predicted values (22.12 U/mL and 1.36 U/mg). Optimal activity of the crude CEP occurred at pH 8.0 and 40 °C. It is a metallopeptidase, activated by Ca2+, inhibited by Zn2+ and ethylene-diamine-tetra-acetic acid, and a serine proteinase which is inhibited by phenylmethylsulfonyl fluoride. Kinetic studies showed that CEP from LP69 could hydrolyze whey protein, lactoglobulin and casein. Our study improves the extraction efficiency of CEPs from LP69, providing the reference for their industrial development.

Binding of 3-phosphoglycerate leads to both activation and stabilisation of ADP-glucose pyrophosphorylase from apple leaves

2005 ◽  
Vol 32 (9) ◽  
pp. 839
Author(s):  
Rui Zhou ◽  
Lailiang Cheng
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Enzyme Activity ◽  
Inorganic Phosphate ◽  
Thermal Inactivation ◽  
Specific Activity ◽  
Apple Leaves ◽  
Apparent Homogeneity ◽  
Adp Glucose Pyrophosphorylase ◽  
High Concentrations

Apple leaf ADP-glucose pyrophosphorylase was purified 1436-fold to apparent homogeneity with a specific activity of 58.9 units mg–1. The enzyme was activated by 3-phosphoglycerate (PGA) and inhibited by inorganic phosphate (Pi) in the ADPG synthesis direction. In the pyrophosphorolytic direction, however, high concentrations of PGA (> 2.5 mm) inhibited the enzyme activity. The enzyme was resistant to thermal inactivation with a T0.5 (temperature at which 50% of the enzyme activity is lost after 5 min incubation) of 52°C. Incubation with 2 mm PGA or 2 mm Pi increased T0.5 to 68°C. Incubation with 2 mm dithiothreitol (DTT) decreased T0.5 to 42°C, whereas inclusion of 2 mm PGA in the DTT incubation maintained T0.5 at 52°C. DTT-induced decrease in thermal stability was accompanied by monomerisation of the small subunits. Presence of PGA in the DTT incubation did not alter the monomerisation of the small subunits of the enzyme induced by DTT. These findings indicate that binding of PGA renders apple leaf AGPase with a conformation that is not only more efficient in catalysis but also more stable to heat treatment. The physiological significance of the protective effect of PGA on thermal inactivation of AGPase is discussed.

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