EFFECT OF CERTAIN CATIONS ON ACTIVITY OF LEUCINE NAPHTHYLAMIDASES OF PARAMECIUM CAUDATUM

1967 ◽  
Vol 13 (9) ◽  
pp. 1133-1138 ◽  
Author(s):  
Norvell W. Hunter
Keyword(s):  
Enzymatic Activity ◽  
Maximum Activity ◽  
Paramecium Caudatum ◽  
Optimum Activity ◽  
Spectrophotometric Methods

Spectrophotometric methods were used to study the activity of the leucine naphthylamidases of Paramecium caudatum. Optimum activity of the enzymes occurred from pH 6.6 to 6.8 and was enhanced by either Co2+, Mn2+, or by Mg2+. Maximum activity occurred when Co2+ was used with either Mg2+ or Mn2+. Activity was depressed by either Sr2+, Fe2+, Zn2+, Ni2+, Hg2+, Cd2+, Pb2+, Sn2+, or Li2+, and not affected by Ba2+, Cu2+, and Ca2+. Approximately 40% of the enzymatic activity was inhibited by EDTA. Most of this inhibition was reversed by either Mg2+, Co2+, or Mn2+.

scholarly journals Effect of pH on the Electrochemical Behavior of Hydrogen Peroxide in the Presence of Pseudomonas aeruginosa

2021 ◽  
Vol 9 ◽  
Author(s):  
Javier Espinoza-Vergara ◽  
Paulo Molina ◽  
Mariana Walter ◽  
Miguel Gulppi ◽  
Nelson Vejar ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pseudomonas Aeruginosa ◽  
Enzymatic Activity ◽  
Electrochemical Behavior ◽  
Electrochemical Techniques ◽  
Stable State ◽  
Reduction Reaction ◽  
Maximum Activity ◽  
Open Circuit ◽  
Mueller Hinton

The influence of pH on the electrochemical behavior of hydrogen peroxide in the presence of Pseudomonas aeruginosa was investigated using electrochemical techniques. Cyclic and square wave voltammetry were used to monitor the enzymatic activity. A modified cobalt phthalocyanine (CoPc) carbon electrode (OPG), a known catalyst for reducing O2 to H2O2, was used to detect species resulting from the enzyme activity. The electrolyte was a sterilized aqueous medium containing Mueller-Hinton (MH) broth. The open-circuit potential (OCP) of the Pseudomonas aeruginosa culture in MH decreased rapidly with time, reaching a stable state after 4 h. Peculiarities in the E / I response were observed in voltammograms conducted in less than 4 h of exposure to the culture medium. Such particular E/I responses are due to the catalase’s enzymatic action related to the conversion of hydrogen peroxide to oxygen, confirming the authors’ previous findings related to the behavior of other catalase-positive microorganisms. The enzymatic activity exhibits maximum activity at pH 7.5, assessed by the potential at which oxygen is reduced to hydrogen peroxide. At higher or lower pHs, the oxygen reduction reaction (ORR) occurs at higher overpotentials, i.e., at more negative potentials. In addition, and to assess the influence of bacterial adhesion on the electrochemical behavior, measurements of the bacterial-substrate metal interaction were performed at different pH using atomic force microscopy.

scholarly journals Purification and Partial Characterization of β-Glucosidase from Fresh Leaves of Tea Plants (Camellia sinensis (L.) O. Kuntze)

2005 ◽  
Vol 37 (6) ◽  
pp. 363-370 ◽  
Author(s):  
Ye-Yun Li ◽  
Chang-Jun Jiang ◽  
Xiao-Chun Wan ◽  
Zheng-Zhu Zhang ◽  
Da-Xiang Li
Keyword(s):  
Specific Activity ◽  
Gel Filtration ◽  
Maximum Activity ◽  
Exchange Chromatography ◽  
Optimum Activity ◽  
Development Of Resistance ◽  
Sds Page ◽  
C 50 ◽  
Tea Plants

Abstractβ-Glucosidases are important in the formation of floral tea aroma and the development of resistance to pathogens and herbivores in tea plants. A novel β-glucosidase was purified 117-fold to homogeneity, with a yield of 1.26%, from tea leaves by chilled acetone and ammonium sulfate precipitation, ion exchange chromatography (CM-Sephadex C-50) and fast protein liquid chromatography (FPLC; Superdex 75, Resource S). The enzyme was a monomeric protein with specific activity of 2.57 U/mg. The molecular mass of the enzyme was estimated to be about 41 kDa and 34 kDa by SDS-PAGE and FPLC gel filtration on Superdex 200, respectively. The enzyme showed optimum activity at 50 °C and was stable at temperatures lower than 40 °C. It was active between pH 4.0 and pH 7.0, with an optimum activity at pH 5.5, and was fairly stable from pH 4.5 to pH 8.0. The enzyme showed maximum activity towards pNPG, low activity towards pNP-Galacto, and no activity towards pNP-Xylo.

scholarly journals Sugarcane bagasse as a source of carbon for enzyme production by filamentous fungi1

Hoehnea ◽  
2018 ◽  
Vol 45 (1) ◽  
pp. 134-142 ◽  
Author(s):  
Flaviane Lopes Ferreira ◽  
Cesar Barretta Dall'Antonia ◽  
Emerson Andrade Shiga ◽  
Larissa Juliani Alvim ◽  
Rosemeire Aparecida Bom Pessoni
Keyword(s):  
Carbon Source ◽  
Enzymatic Activity ◽  
Sugarcane Bagasse ◽  
Enzyme Production ◽  
Sole Carbon Source ◽  
Sole Source ◽  
Maximum Activity ◽  
Liquid Media ◽  
Biotechnological Potential ◽  
Efficient Producer

ABSTRACT The aim of the present work was to assess the enzymatic activity of six strains of filamentous fungi grown in liquid media containing 1% sugarcane bagasse as the sole carbon source. All fungal strains were able to use this agro-industrial residue, producing various types of enzymes, such as cellulases, xylanases, amylases, pectinases, and laccases. However, Aspergillus japonicus Saito was the most efficient producer, showing the highest enzymatic activity for laccase (395.73 U L-1), endo-β-1,4-xylanase (3.55 U mL-1) and β-xylosidase (9.74 U mL-1) at seven, fourteen and twenty-one days in culture, respectively. Furthermore, the endo-β-1,4-xylanases and β-xylosidases of A. japonicus showed maximum activity at 50°C, and pH 5.5 and pH 3.5-4.5, respectively. Thus, these results indicate that A. japonicus has a great biotechnological potential for the production of these enzymes using sugarcane bagasse as the sole source of carbon.

scholarly journals An Active of Extracellular Cellulose Degrading Enzyme from Termite Bacterial Endosimbiont

2016 ◽  
Vol 20 (1) ◽  
pp. 62
Author(s):  
M. Saifur Rohman ◽  
Endang Pamulatsih ◽  
Yudi Kusnadi ◽  
Triwibowo Yuwono ◽  
Erni Martani
Keyword(s):  
Enzymatic Activity ◽  
Maximum Activity ◽  
Enzymatic Activities ◽  
Enzymatic Assay ◽  
Glycosidic Bond ◽  
Acidic Ph ◽  
Total Proteins ◽  
Degrading Enzyme ◽  
Paenibacillus Sp ◽  
Simple Carbohydrate

Cellulase is an ezyme that specifically cleaves the 1,4-β-glycosidic bond of cellulose to produce thesmall fragments of simple carbohydrate. This work was aimed to characterize the extracellular cellulase fromPaenibacillus spp., which was previously isolated from macro termites, Odontotermes bhagwatii in our laboratory.Two Paenibacillus isolates were used in this experiment, namely Paenibacillus cellulositrophicus SBT1 andPaenibacillus, sp. SBT8. Analysis of the total proteins in the supernatants showed that P. cellulositrophicus SBT1and Paenibacillus sp. SBT8 roughly produced as much as 18.6 mg/l and 24.8 mg/l of extracellular cellulases,respectively. Enzymatic assay showed that SBT1 and SBT8 cellulase exhibited enzymatic acitivity of 0.17 U/mg and 0.12 U/mg, respectively. Temperature dependencies analysis indicated that both cellulases exhibitedmaximum activity at 35oC. At the temperature higher than 55oC, the enzymatic activities of both cellulases wereroughly 20% reduced compared to the maximum activity. SBT1 and SBT8 cellulases were both active at acidicpH. At basic pH (pH 8) the enzymatic activities of both cellulases were reduced roughly 30% compared to thatof acidic pH. Supplementing of Mg2+, Zn2+, and Ca2+ in range of 1-10 mM increased the enzymatic activity ofboth cellulases roughly 33 to 50%.

scholarly journals Biocatalytic properties of horseradish root extract peroxidase (HRP)

2014 ◽  
Vol 15 ◽  
pp. 101-103 ◽  
Author(s):  
D Purev ◽  
J Bayarmaa ◽  
S Tsevelmaa ◽  
A Zolzaya
Keyword(s):  
Enzymatic Activity ◽  
Maximum Activity ◽  
Root Extract ◽  
Temperature Influence ◽  
Optimum Temperature

The objective of the present work was to examine biocatalytic properties of peroxidase in horseradish acclimatized in our country. We have found that horseradish root extract’s peroxidase (HRP) has Km 2.5 mM and Vmax 5.36 mM·s-1. Maximum activity (pHopt) was estimated at pH 6.0 and enzyme is more stable in alkali, than in acid. The optimum temperature (Topt) for HRP is 40oC and the enzyme is not stable to temperature influence. The horseradish  root’s extract retains enzymatic activity within 21 days. DOI: http://doi.dx.org/10.5564/mjc.v15i0.332 Mongolian Journal of Chemistry 15 (41), 2014, p101-103

scholarly journals Contribution of the active-site metal cation to the catalytic activity and to the conformational stability of phosphotriesterase: temperature- and pH-dependence

2004 ◽  
Vol 380 (3) ◽  
pp. 627-633 ◽  
Author(s):  
Daniel ROCHU ◽  
Nathalie VIGUIÉ ◽  
Frédérique RENAULT ◽  
David CROUZIER ◽  
Marie-Thérèse FROMENT ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Cation ◽  
Active Site ◽  
Ph Dependence ◽  
Conformational Stability ◽  
Maximum Activity ◽  
Active Centre ◽  
Optimum Activity ◽  
Maximum Stability ◽  
Activation Phase

Phosphotriesterase (PTE) detoxifies nerve agents and organophosphate pesticides. The two zinc cations of the PTE active centre can be substituted by other transition metal cations without loss of activity. Furthermore, metal-substituted PTEs display differences in catalytic properties. A prerequisite for engineering highly efficient mutants of PTE is to improve their thermostability. Isoelectric focusing, capillary electrophoresis and steady-state kinetics analysis were used to determine the contribution of the active-site cations Zn2+, Co2+ or Cd2+ to both the catalytic activity and the conformational stability of the corresponding PTE isoforms. The three isoforms have different pI values (7.2, 7.5 and 7.1) and showed non-superimposable electrophoretic titration curves. The overall structural alterations, causing changes in functional properties, were found to be related to the nature of the bound cation: ionic radius and ion electronegativity correlate with Km and kcat respectively. In addition, the pH-dependent activity profiles of isoforms were different. The temperature-dependent profiles of activity showed maximum activity at T≤35 °C, followed by an activation phase near 45–48 °C and then inactivation which was completed at 60 °C. Analysis of thermal denaturation of the PTEs provided evidence that the activation phase resulted from a transient intermediate. Finally, at the optimum activity between pH 8 and 9.4, the thermostability of the different PTEs increased as the pH decreased, and the metal cation modulated stability (Zn2+-, Co2+- and Cd2+-PTE showed different Tm values of 60.5–67 °C, 58–64 °C and 53–64 °C respectively). Requirements for optimum activity of PTE (displayed by Co2+-PTE) and maximum stability (displayed by Zn2+-PTE) were demonstrated.

Partial purification and some properties of a neutral sulfhydryl and an acid proteinase from Entamoeba histolytica

1977 ◽  
Vol 23 (4) ◽  
pp. 420-425 ◽  
Author(s):  
John McLaughlin ◽  
Gaetan Faubert
Keyword(s):  
Entamoeba Histolytica ◽  
Cathepsin D ◽  
Metal Ion ◽  
Protozoan Parasite ◽  
Maximum Activity ◽  
Partial Purification ◽  
Acid Proteinase ◽  
Neutral Proteinase ◽  
Optimum Activity ◽  
Serum Albumen

The partial purification of two intracellular proteinases from the protozoan parasite Entamoeba histolytica is reported. One of these enzymes is an acid proteinase exhibiting maximum activity at pH 3.5 (hemoglobin substrate), is little affected by a range of inhibitors or activators, and is presumed to be similar to cathepsin D. Also present is a neutral proteinase exhibiting optimum activity at pH 6.0 (azocasein) but only poorly hydrolyzing either hemoglobin or serum albumen. This latter enzyme displayed no metal ion requirement, but was markedly inhibited by thiol-blocking agents and activated by free sulfhydryl-containing compounds.

Cinnamate-4-Hydroxyiase in Polyporus hispidus

1973 ◽  
Vol 51 (6) ◽  
pp. 731-734 ◽  
Author(s):  
C. P. Vance ◽  
A. M. D. Nambudiri ◽  
G. H. N. Towers
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Microsomal Fraction ◽  
Mitochondrial Fraction ◽  
Maximum Activity ◽  
Coumaric Acid ◽  
Free System ◽  
Optimum Ph ◽  
A Cell ◽  
Plant Enzyme

A cell-free system capable of hydroxylating cinnamic acid to p-coumaric acid has been isolated from 10-day-oid cultures of Polyporus hispidus. The enzyme requires NADPH and FAD for maximum activity. Enzyme activity appears to be localized in the microsomal fraction with slight activity occurring in the mitochondrial fraction. The optimum pH for enzymatic activity is 7.5. This is the first report on any properties of this enzyme in a fungus. The enzyme differs from the known plant enzyme in its FAD requirement.

Preparation and Characterization of Immobilized α-Amylase

2012 ◽  
Vol 602-604 ◽  
pp. 1186-1189
Author(s):  
Zhi Jie Geng ◽  
Song Bai Lin ◽  
Gao Shuang Huang ◽  
Ai Ru Ke
Keyword(s):  
Aqueous Solution ◽  
Enzymatic Activity ◽  
Immobilized Enzyme ◽  
Kinetic Studies ◽  
Maximum Activity ◽  
Solution Polymerization ◽  
Adsorption Method ◽  
Aqueous Solution Polymerization

P(DMAA-co-AM)hydrogel; adsorption method; a-amylase; Immobilized enzyme. Abstract. P(DMAA-co-AM)hydrogel was prepared by aqueous solution polymerization with N,N-dimethylacrylamide(DMAA) and acrylamide(AM) as monomers.,taking the P(DMAA-co-AM) hydrogel as carrier, a-amylase was immobilized by adsorption method.The investigation of effection of temperature and pH on enzymatic activity exhibites that the optimum temperatures are 50°C for both free and immobilized enzyme,the maximum activity is observed at pH 6.0 for both free and immobized enzyme. The activity of immobilized a-amylase remaines higher 40% at sixth run. Kinetic studies demonstrate that: Km values are 5.15749 and 1.44479 mg/mL for free and immobilized enzyme, Vmax values are 2.56082 and 0.58272 mg/mL min-1 for free and immobilized enzyme.

scholarly journals Metaproteomic Discovery and Characterization of a Novel Lipolytic Enzyme From an Indian Hot Spring

2021 ◽  
Vol 12 ◽  
Author(s):  
Dennis Sander ◽  
Yanfei Yu ◽  
Premankur Sukul ◽  
Sina Schäkermann ◽  
Julia E. Bandow ◽  
...  
Keyword(s):  
Chain Length ◽  
Prolonged Exposure ◽  
Hot Spring ◽  
Hydrolytic Activity ◽  
Industrial Applications ◽  
Maximum Activity ◽  
Lipolytic Enzyme ◽  
Lipolytic Enzymes ◽  
Optimum Activity ◽  
Solvent Stable

Lipolytic enzymes are produced by animals, plants and microorganisms. With their chemo-, regio-, and enantio-specific characteristics, lipolytic enzymes are important biocatalysts useful in several industrial applications. They are widely used in the processing of fats and oils, detergents, food processing, paper and cosmetics production. In this work, we used a new functional metaproteomics approach to screen sediment samples of the Indian Bakreshwar hot spring for novel thermo- and solvent-stable lipolytic enzymes. We were able to identify an enzyme showing favorable characteristics. DS-007 showed high hydrolytic activity with substrates with shorter chain length (<C8) with the maximum activity observed against p-nitrophenyl butyrate (C4). For substrates with a chain length >C10, significantly less hydrolytic activity was observed. A preference for short chain acyl groups is characteristic for esterases, suggesting that DS-007 is an esterase. Consistent with the high temperature at its site of isolation, DS-007 showed a temperature optimum at 55°C and retained 80% activity even after prolonged exposure to temperatures as high as 60°C. The enzyme showed optimum activity at pH 9.5, with more than 50% of its optimum activity between pH 8.0 and pH 9.5. DS-007 also exhibited tolerance toward organic solvents at a concentration of 1% (v/v). One percent of methanol increased the activity of DS-007 by 40% in comparison to the optimum conditions without solvent. In the presence of 10% methanol, DMSO or isopropanol DS-007 still showed around 50% activity. This data indicates that DS-007 is a temperature- and solvent-stable thermophilic enzyme with reasonable activity even at lower temperatures as well as a catalyst that can be used at a broad range of pH values with an optimum in the alkaline range, showing the adaptation to the habitat’s temperature and alkaline pH.

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