scholarly journals Immobilization of Naringinase from Penicillium decumbens on Chitosan Microspheres for Debittering Grapefruit Juice

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4234 ◽  
Author(s):  
Joanna Bodakowska-Boczniewicz ◽  
Zbigniew Garncarek
Keyword(s):  
Grapefruit Juice ◽  
Immobilized Enzyme ◽  
Maximum Activity ◽  
Chitosan Microspheres ◽  
Optimum Ph ◽  
Potential Applicability ◽  
Km Value ◽  
Hydrolysis Of ◽  
Thermal Stability Of

Naringinase is an enzyme complex which exhibits α-l-rhamnosidase and β-d-glucosidase activity. This enzymatic complex catalyzes the hydrolysis of naringin (4′,5,7-trihydroxy flavanone 7-rhamnoglucoside), the main bittering component in grapefruit. Reduction of the level of this substance during the processing of juice has been the focus of many studies. The aim of the study was the immobilization of naringinase on chitosan microspheres activated with glutaraldehyde and, finally, the use of such immobilized enzyme for debittering grapefruit juice. The effect of naringinase concentration and characterization of the immobilized enzyme compared to the soluble enzyme were investigated. The maximum activity was observed at optimum pH 4.0 for both free and immobilized naringinase. However, the optimum temperature was shifted from 70 to 40 °C upon immobilization. The KM value of the immobilized naringinase was higher than that of soluble naringinase. The immobilization did not change the thermal stability of the enzyme. The immobilized naringinase had good operational stability. This preparation retained 88.1 ± 2.8% of its initial activity after ten runs of naringin hydrolysis from fresh grapefruit juice. The results indicate that naringinase immobilized on chitosan has potential applicability for debittering and improving the sensory properties of grapefruit juices.

scholarly journals Purification and characterization of acid phosphatase from a germinating black gram (Vigna mungo L.) seedling

2011 ◽  
Vol 63 (3) ◽  
pp. 747-756 ◽  
Author(s):  
A.K.M. Asaduzzaman ◽  
Habibur Rahman ◽  
Tanzima Yeasmin
Keyword(s):  
Acid Phosphatase ◽  
Gel Electrophoresis ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Inhibitory Effect ◽  
Maximum Activity ◽  
Exchange Chromatography ◽  
Black Gram ◽  
Km Value

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.

scholarly journals Structural and Catalytic Characterization of TsBGL, a β-Glucosidase From Thermofilum sp. ex4484_79

2021 ◽  
Vol 12 ◽  
Author(s):  
Anke Chen ◽  
Dan Wang ◽  
Rui Ji ◽  
Jixi Li ◽  
Shaohua Gu ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Specific Activity ◽  
Maximum Activity ◽  
Homologous Proteins ◽  
Glycosidic Bonds ◽  
Catalytic Sites ◽  
Potential Applications ◽  
Beta Glucosidase ◽  
Hydrolysis Of

Beta-glucosidase is an enzyme that catalyzes the hydrolysis of the glycosidic bonds of cellobiose, resulting in the production of glucose, which is an important step for the effective utilization of cellulose. In the present study, a thermostable β-glucosidase was isolated and purified from the Thermoprotei Thermofilum sp. ex4484_79 and subjected to enzymatic and structural characterization. The purified β-glucosidase (TsBGL) exhibited maximum activity at 90°C and pH 5.0 and displayed maximum specific activity of 139.2μmol/min/mgzne against p-nitrophenyl β-D-glucopyranoside (pNPGlc) and 24.3μmol/min/mgzen against cellobiose. Furthermore, TsBGL exhibited a relatively high thermostability, retaining 84 and 47% of its activity after incubation at 85°C for 1.5h and 90°C for 1.5h, respectively. The crystal structure of TsBGL was resolved at a resolution of 2.14Å, which revealed a classical (α/β)8-barrel catalytic domain. A structural comparison of TsBGL with other homologous proteins revealed that its catalytic sites included Glu210 and Glu414. We provide the molecular structure of TsBGL and the possibility of improving its characteristics for potential applications in industries.

Isolation and Partial Characterization of Alcohol Dehydrogenase From Broad Bean (Vicia faba)

1974 ◽  
Vol 1 (4) ◽  
pp. 579 ◽  
Author(s):  
S Leblova
Keyword(s):  
Thermal Stability ◽  
Alcohol Dehydrogenase ◽  
Broad Bean ◽  
Plant Tissues ◽  
Growth Substances ◽  
Ph Optimum ◽  
Alcohol Dehydrogenase Activity ◽  
Km Value ◽  
Thermal Stability Of

Alcohol dehydrogenase isolated from broad bean was found to have a Km value of 1.0 × 1.0 -2 M, a pH optimum of 8.7 and a molecular weight of 60 000 � 5000. The enzyme lost 55 % of its activity after being heated at 55�C, and was totally inactivated at 70°C. Thermal stability of the enzyme was not enhanced by NAD+ or ethanol. The substrate specificity of the enzyme is reported. Cysteine and mercaptoethanol activated the enzyme, whilep-chloromercuribenzoate, Cu2+, Hg2+, B4O72- -, Zn2+ and EDTA inhibited it. The influence of ethanol, acetaldehyde and growth substances on alcohol dehydrogenase activity in germinating broad bean seeds and plant tissues was also studied.

Glycosidases in bovine milk: α-mannosidase and its inhibition by zwitterions

1968 ◽  
Vol 46 (11) ◽  
pp. 1351-1356 ◽  
Author(s):  
A. Mellors ◽  
V. R. Harwalkar
Keyword(s):  
Amino Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Bovine Milk ◽  
Maximum Activity ◽  
Manganese Ions ◽  
Ammonium Sulfate Precipitation ◽  
Optimum Ph ◽  
High Concentrations ◽  
Hydrolysis Of ◽  
Dibasic Amino Acids

α-Mannosidase is present in bovine milk and is associated with the β-casein fraction following polyacrylamide gel electrophoresis. It was separated from the casein complex by ammonium sulfate precipitation in the presence of 10% (v/v) ethanol. Zinc or manganese ions are required for maximum activity and the enzyme is very labile. The optimum pH for the hydrolysis of p-nitrophenyl α-mannoside is about 3. In the presence of amino acid buffers the enzyme is inhibited. For dibasic amino acids this inhibition is inversely related to the [Formula: see text] of the amino acid and is apparently due to inhibition by zwitterions. High concentrations of the substrate p-nitrophenyl α-mannoside are inhibitory, and the apparent Km for this hydrolysis is 1.2 mM.

scholarly journals Molecular Characterization of Cycloinulooligosaccharide Fructanotransferase from Bacillus macerans

2001 ◽  
Vol 67 (2) ◽  
pp. 995-1000 ◽  
Author(s):  
Hwa-Young Kim ◽  
Yong-Jin Choi
Keyword(s):  
Escherichia Coli ◽  
Thermal Stability ◽  
Striking Difference ◽  
Bacillus Macerans ◽  
Specific Manner ◽  
Specificity Constant ◽  
Processing Event ◽  
Hydrolysis Of ◽  
Thermal Stability Of

ABSTRACT Cycloinulooligosaccharide fructanotransferase (CFTase) converts inulin into cyclooligosaccharides of β-(2→1)-linkedd-fructofuranose by catalyzing an intramolecular transfructosylation reaction. The CFTase gene was cloned and characterized from Bacillus macerans CFC1. The CFTase gene encoded a polypeptide of 1,333 amino acids with a calculatedM r of 149,563. Western blot and zymography analyses revealed that the CFTase with a molecular mass of 150 kDa (CFT150) was processed (between Ser389 and Phe390 residue) to form a 107-kDa protein (CFT107) in the B. macerans CFC1 cells. The processed CFT107 was similar in its mass to the previously purified CFTase from B. macerans CFC1. The CFT107 enzyme was produced by B. macerans CFC1 but was not detected from the recombinant Escherichia coli cells, indicating that the processing event occurred in a host-specific manner. The two CFTases (CFT150 and CFT107) exhibited the same enzymatic properties, such as influences of pH and temperature on the enzyme activity, the intermolecular transfructosylation ability, and the ability of hydrolysis of cycloinulooligosaccharides produced by the cyclization reaction. However, the thermal stability of CFT107 was slightly higher than that of CFT150. The most striking difference between the two enzymes was observed in their Km values; the value for CFT150 (1.56 mM) was threefold lower than that for CFT107 (4.76 mM). Thus, the specificity constant (k cat/Km ) of CFT150 was about fourfold higher than that of CFT107. These results indicated that the N-terminal 358-residue region of CFT150 played a role in increasing the enzyme's binding affinity to the inulin substrate.

scholarly journals Identification and Characterization of Bacterial Lipase from Plateu Soil in West Java

2017 ◽  
Vol 18 (02) ◽  
pp. 103-108
Author(s):  
Vivitri Dewi Prasasty ◽  
Vinella Winata ◽  
Muhammad Hanafi
Keyword(s):  
Heat Stability ◽  
Industrial Applications ◽  
West Java ◽  
Ph Optimum ◽  
Good Efficiency ◽  
Optimum Ph ◽  
Glycerol Ester ◽  
Lipase Screening ◽  
Hydrolysis Of

Lipases are known as glycerol ester hydrolases that catalyze the hydrolysis of triglycerides into free fatty acids and glycerol. Lipases are found in human, animal, plant, and microorganisms. The aim of this research is to identify lipase producers and characterize bacterial lipase from West Java plateau soil. Plateau soil bacteria samples were isolated on lipase screening medium containing Rhodamine B. Olive oil was used as a substrate in screening and production medium bacterial lipases. From 16 bacterial isolate of lipase producers, 14 were identified as Bacillus sp. and the others were identified as Pseudomonas alcaligenes. All isolates were taken into production step to determine their lipase activities. Moreover, top 3 lipase activities out of 16 lipase activities were chosen to find the optimum pH and temperature. Both characterizations showed pH optimum and temperature optimum from each lipase. These optimum condition were used in heat stability characterization for each lipase samples. The result showed that lipase from isolate COK 2 in optimum pH 4 and temperature 50oC was the most stable lipase due to this sample has good and stable activity for 1 to 5 hours incubation time. Lipase sample from isolate COK 2 has good efficiency for lipase productivity in acid condition and high temperature. Results of this investigation could encourage utilization of these activity enhancers for various industrial applications.

Characterization of 2β(R)-17-O-AcetylajmaIan: Acetylesterase — a Specific Enzyme Involved in the Biosynthesis of the Rauwolfia Alkaloid Ajmaline

1987 ◽  
Vol 42 (4) ◽  
pp. 333-342 ◽  
Author(s):  
Leo Polz ◽  
Helmut Schübel ◽  
Joachim Stoekigt
Keyword(s):  
Substrate Selectivity ◽  
Specific Enzyme ◽  
Naturally Occurring ◽  
Optimum Ph ◽  
Relative Molecular Weight ◽  
Inhibition Studies ◽  
Hydrolysis Of ◽  
Activity Point ◽  
Rauwolfia Alkaloid

A novel enzyme was isolated, partially purified (217-fold) and characterized from cell suspen­sion cultures of Rauwolfia serpentina Benth. The enzyme catalyzes one of the late biochemical reactions in the biosynthesis of ajmaline by hydrolysis of 17-O-acetylated alkaloids of the ajmalan group forming the appropriate deacetylated compounds. This esterase exhibits an unusually high substrate selectivity and exclusively accepts acetylated ajmaline derivatives with the naturally occurring 2β(R)-configuration. The properties of the enzyme were determined showing an optimum pH at 7.5, an isoelectric point of pH 4.9 and a relative molecular weight of 33 ± 2 kDa. Inhibition studies of enzyme activity point to the necessity of SH-groups. The esterase seems not to be inhibited by ajmaline. the end product of the pathway. The highest enzyme activities were observed in leaves and cell suspension tissues of the tribe Rauwolfieae which are known to synthe­size ajmaline and its congeners. The specific function of the esterase in the biosynthesis of the later alkaloids was established.

α-Amylase Aspergillus oryzae Immobilized on Modified Expanded Perlite

2014 ◽  
Vol 12 (1) ◽  
pp. 587-596 ◽  
Author(s):  
J. Rodriguez ◽  
F. Soria ◽  
H. Geronazzo ◽  
H. Destefanis
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aspergillus Oryzae ◽  
Immobilized Enzyme ◽  
Maximum Activity ◽  
Free Enzyme ◽  
Expanded Perlite ◽  
Initial Activity ◽  
Optimum Ph ◽  
Scanning Electron

Abstract The α-amylase from Aspergillus oryzae was immobilized covalently onto expanded perlite (EP) and modified EP by treatment with TiO2 (EP-TiO2), dye HE3B (EP-HE3B) polyethylene terephthalate (PET)-hydrazide (EP-PET) and magnetite (EP-magnetite). The modified EP was characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The supports were functionalized with aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA). The optimum pH for free and immobilized α-amylase was 5.5. Temperature of maximum activity for free enzyme and immobilized enzyme on EP-HE3B was 50°C. The immobilized enzyme in EP-APTES this value was 55°C. The immobilized α-amylase in EP-APTES and EP-HE3B-APTES exhibited better thermostability than free enzyme. The immobilized derivatives showed moderate operational stability by retaining 50% of initial activity after seven successive reuses.

Characterization of amoA and hao Genes Responsible for Ammonia Oxidation Reaction in CANON System

2011 ◽  
Vol 183-185 ◽  
pp. 1014-1019
Author(s):  
Hai Yan Zou ◽  
Jun Li Huang ◽  
Fang Fang ◽  
Jin Song Guo
Keyword(s):  
Nitrogen Removal ◽  
Oxidation Reaction ◽  
High Efficiency ◽  
Ammonia Oxidation ◽  
Residual Activity ◽  
Maximum Activity ◽  
Ammonia Oxidizing Bacteria ◽  
Hydroxylamine Oxidoreductase ◽  
Optimum Ph

In this research the genes (amoA and hao) for ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO) responsible for ammonia oxidation reaction in completely autotrophic nitrogen removal over nitrite process were cloned and sequenced, and the recombinant protein of AMO and HAO was expressed and characterized. The optimum temperature for AMO activity was 55 °C and more than 40% of the maximum activity was retained from 15-50 °C. The optimum pH for the enzyme was found to be pH 11.0. The highest activity for HAO was observed at 45 °C. More than 50% of the maximum activity was retained even at 55 °C. The dependence of HAO on pH was strong and only average 15% of residual activity left at pH ranging from 3.0-9.0. Study on the molecular and biochemistry properties of recombinant AMO and HAO will benefit for the manipulation of ammonia-oxidizing bacteria to achieve the goal of high efficiency of nitrogen removal.

Post-proline endopeptidase. Partial purification and characterization of the enzyme from pig kidneys

1982 ◽  
Vol 47 (4) ◽  
pp. 1139-1148 ◽  
Author(s):  
Karel Hauzer ◽  
Linda Servítová ◽  
Tomislav Barth ◽  
Karel Jošt
Keyword(s):  
Specific Activity ◽  
Gel Filtration ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Partial Purification ◽  
Purification And Characterization ◽  
Optimum Ph ◽  
Hydrolysis Of ◽  
Prolyl Leucyl Glycinamide

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.

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