Study on the Process of the Reaction Catalyzed by Polyphenol Oxidase from Purple Sweet Potato

2014 ◽  
Vol 898 ◽  
pp. 153-156 ◽  
Author(s):  
Lu Gao ◽  
Li Chun Zhao ◽  
Ji Dong Duan ◽  
Yan Li Tao
Keyword(s):  
Sweet Potato ◽  
Polyphenol Oxidase ◽  
Substrate Concentration ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Enzyme Concentration ◽  
Buffer Solution ◽  
Purple Sweet Potato ◽  
The Relationship ◽  
Substrate Concentrations

The polyphenol oxidase (PPO) was extracted from fresh purple sweet potato (PSP) by phosphate buffer solution, and spectrophotometry method was applied in the experiment. The process of the reaction catalyzed by PPO with different substrate concentrations and the relationship between enzyme concentrations and PPO activity were mainly studied here. The result showed that the effect of enzyme concentration on PPO activity was stronger than that of substrate concentration on PPO activity.

scholarly journals The determination of binding parameters when the total and free substrate concentrations are not approximately equal

1979 ◽  
Vol 179 (3) ◽  
pp. 697-700 ◽  
Author(s):  
N Gains
Keyword(s):  
Substrate Concentration ◽  
Graphical Method ◽  
Enzyme Concentration ◽  
Binding Parameters ◽  
Free Concentration ◽  
Equilibrium Binding ◽  
Substrate Concentrations

By using a standard graphical method values of Km and V may be found that are independent of the conditions and assumptions that the total substrate concentration approximates to its free concentration and that Km is much larger than the enzyme concentration. The procedure is also applicable to the determination of equilibrium binding parameters of a ligand to a macromolecule.

Bioceramic Hydroxyapatite Granules for Purification of Biotechnological Products

2011 ◽  
Vol 284-286 ◽  
pp. 1764-1769 ◽  
Author(s):  
Vitalijs Lakevics ◽  
Janis Locs ◽  
Dagnija Loca ◽  
Valentina Stepanova ◽  
Liga Berzina-Cimdina ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Phosphate Buffer ◽  
Bovine Serum ◽  
Phosphate Buffer Solution ◽  
Sorption Process ◽  
Buffer Solution ◽  
Ph Values ◽  
Bovine Serum Albumin Adsorption ◽  
Albumin Adsorption

Sorption experiments of bovine serum albumin (BSA) on hydroxyapatite (HAp) ceramic granules, prepared at three temperatures 900°C, 1000°C and 1150°C were performed at room temperature 18,6 °C and phosphate buffer, pH 5,83; 6.38 and 7,39. Thermal treatment contributed to the decrease of bovine serum albumin immobilization indicating that sorption process depended on HAp ceramics specific surface area and pH values of phosphate buffer solution. However, it was confirmed that granule size was also an important parameter for bovine serum albumin adsorption. As a result of these experiments, the most appropriate adsorption conditions and phosphate buffer pH values influence on to BSA sorption were analyzed.

Reduction of Escherichia coli O157:H7 Counts on Whole Fresh Apples by Treatment with Sanitizers

2000 ◽  
Vol 63 (6) ◽  
pp. 703-708 ◽  
Author(s):  
MARCY A. WISNIEWSKY ◽  
BONITA A. GLATZ ◽  
MARK L. GLEASON ◽  
CHERYLL A. REITMEIER
Keyword(s):  
Escherichia Coli ◽  
Chlorine Dioxide ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
Water Control ◽  
Buffer Solution ◽  
E Coli ◽  
Log Reduction

The objectives of this study were to determine if washing of whole apples with solutions of three different sanitizers (peroxyacetic acid, chlorine dioxide, or a chlorine-phosphate buffer solution) could reduce a contaminating nonpathogenic Escherichia coli O157:H7 population by 5 logs and at what sanitizer concentration and wash time such a reduction could be achieved. Sanitizers were tested at 1, 2, 4, 8, and 16 times the manufacturer's recommended concentration at wash times of 5, 10, and 15 min. Whole, sound Braeburn apples were inoculated with approximately 1 × 108 or 7 × 106 CFU per apple, stored for 24 h, then washed with sterile water (control) or with sanitizers for the prescribed time. Recovered bacteria were enumerated on trypticase soy agar. Washing with water alone reduced the recoverable population by almost 2 logs from the starting population; this can be attributed to physical removal of organisms from the apple surface. No sanitizer, when used at the recommended concentration, reduced the recovered E. coli population by 5 logs under the test conditions. The most effective sanitizer, peroxyacetic acid, achieved a 5-log reduction when used at 2.1 to 14 times its recommended concentration, depending on the length of the wash time. The chlorine-phosphate buffer solution reduced the population by 5 logs when used at 3 to 15 times its recommended concentration, depending on wash time. At no concentration or wash time tested did chlorine dioxide achieve the 5-log reduction.

Electrocatalytic performance of a zinc sulphide nanoparticles-modified carbon paste electrode for the simultaneous determination of acetaminophen, guanine and adenine

2018 ◽  
Vol 10 (11) ◽  
pp. 1362-1371 ◽  
Author(s):  
Mallappa Mahanthappa ◽  
Nagaraju Kottam ◽  
Shivaraj Yellappa
Keyword(s):  
Carbon Paste Electrode ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Zinc Sulphide ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Guanine And Adenine ◽  
Paste Electrode

The simultaneous electroanalysis of acetaminophen (AC), guanine (G) and adenine (A) was successfully achieved on the zinc sulphide nanoparticles-modified carbon paste electrode (ZnS NPs/CPE) in phosphate buffer solution (PBS).

Standardization of substrate and buffer concentrations for in-vivo nitrate reductase activity in Adenanthera microsperma leaves

2015 ◽  
Vol 38 (4) ◽  
pp. 309-311
Author(s):  
Priyanshu Sharma ◽  
S.P. Chaukiyal ◽  
Meenu Sengar
Keyword(s):  
Nitrate Reductase ◽  
Phosphate Buffer ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Buffer Solution ◽  
Substrate Solution ◽  
Substrate Concentrations

The combination of different substrate concentrations (0.05M, 0.10M, 0.15M, 0.20M and 0.25M, KNO3) with different pH of phosphate buffer (0.10 M and 0.20 M, KH2PO4 of the pH 7.0, 7.5, 7.6, 7.7, and 7.8) solutions were tried for in-vivo nitrate reductase activity of Adenanthera microsperma leaves. Maximum nitrate reductase activity was observed in the combination of buffer solution (0.20M KH2PO4) having pH 7.7 and substrate solution 0.20 M concentration.

Microfluidic concentration enhancement of bio-analyte by temperature gradient focusing via Joule heating by DC plus AC field: A numerical approach

2021 ◽  
pp. 1-17
Author(s):  
Amitava Dutta ◽  
Apurba Kumar Santra ◽  
Ranjan Ganguly
Keyword(s):  
Temperature Gradient ◽  
Joule Heating ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Numerical Approach ◽  
High Concentration ◽  
Buffer Solution ◽  
Temperature Gradient Focusing ◽  
Ac Field ◽  
Target Analyte

Abstract We present a detailed numerical analysis of electrophoresis induced concentration of a bio-analyte facilitated by temperature gradient focusing in a phosphate buffer solution via Joule heating inside a converging-diverging microchannel. The purpose is to study the effects of frequency of AC field and channel width variation on the concentration of target analyte. We tune the buffer viscosity, conductivity and electrophoretic mobility of the analyte such that the electrophoretic velocity of the analyte locally balances the electroosmotic flow of the buffer, resulting in a local build-up of the analyte concentration in a target region. An AC field is superimposed on the applied DC field within the microchannel in such a way that the back pressure effect is minimized, resulting in minimum dispersion and high concentration of the target analyte. Axial transport of fluorescein-Na in the phosphate buffer solution is controlled by inducing temperature gradient through Joule heating. The technique leverages the fact that the buffer's ionic strength and viscosity depends on temperature, which in turn guides the analyte transport. A numerical model is proposed and a finite element-based solution of the coupled electric field, mass, momentum, energy and species equations are carried out. Simulation predict peak of 670-fold concentration of fluorescein-Na is achieved. The peak concentration is found to increase sharply as the channel throat width, while the axial spread of concentrated analyte increases at lower frequency of AC field. The results of the work may improve the design of micro concentrator.

scholarly journals POLYPHENOL OXIDASE AND PEROXIDASE ENZYME ASSAYS IN SWEET POTATO CULTIVARS HARVESTED AT DIFFERENT TIMES

2019 ◽  
Vol 32 (2) ◽  
pp. 537-542
Author(s):  
SAMARA LOPES DE ALMEIDA ◽  
MARIA APARECIDA DOS SANTOS MORAIS ◽  
JOSÉ RICARDO TAVARES DE ALBUQUERQUE ◽  
AURÉLIO PAES BARROS JÚNIOR ◽  
ADRIANO DO NASCIMENTO SIMÕES ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Polyphenol Oxidase ◽  
Phosphate Buffer ◽  
Reaction Times ◽  
Reaction Medium ◽  
Potato Cultivars ◽  
Enzyme Assays ◽  
Minimal Processing ◽  
Continuous Increase ◽  
Peroxidase Enzyme

ABSTRACT Enzyme assays are based on methodologies described in the literature. However, the enzyme kinetics must be adjusted to obtain more reliable results. This study aimed to adjust assays by testing different polyphenol oxidase (PPO) and peroxidase (POD) extract amounts and reaction times in sweet potato cultivars harvested at different times. Sweet potato cultivars Paraná, Mãe de Família, and ESAM1 were harvested at 120, 150, and 180 days after planting and minimally processed. A 0.25 g sample was used to determine PPO and POD activities immediately after minimal processing at each harvest. Extraction was performed in 1500 μL phosphate buffer (0.2 M, pH 6.0). The PPO assay was performed by adding 10-50 μL extract, 1490-1450 μL phosphate buffer (0.2 M, pH 6.0), and 1500 μL catechol (0.2 M). The POD assay was carried out by adding 10-50 μL extract to a reaction medium containing 1790-1750 μL phosphate buffer (0.2 M, pH 6), 100 μl guaiacol (5 g L-1), and 100 μL hydrogen peroxide (0.8 g L-1). In both cases, the evaluated reaction times were 1, 2, and 3 min. In the three cultivars, PPO and POD activities increased with the volume of extract and reaction time at all harvest times. The enzyme extract volume of 10 μL for 2 min promoted a continuous increase in PPO and POD enzyme activities in all studied cultivars and at all reaction times.

scholarly journals Carbon-Based Magnetic Nanocarrier for Controlled Drug Release: A Green Synthesis Approach

2018 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Jessica Oliveira ◽  
Raquel Rodrigues ◽  
Lillian Barros ◽  
Isabel Ferreira ◽  
Luís Marchesi ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Magnetic Nanoparticles ◽  
Drug Release ◽  
Phosphate Buffer ◽  
Colloidal Stability ◽  
Ph Dependence ◽  
Phosphate Buffer Solution ◽  
Controlled Drug Release ◽  
Buffer Solution ◽  
Carbon Based

In this study, hydrophilic magnetic nanoparticles were synthesized by green routes using a methanolic extract of Rubus ulmifolius Schott flowers. The prepared magnetic nanoparticles were coated with carbon-based shell for drug delivery application. The nanocomposites were further chemically functionalized with nitric acid and, sequentially, with Pluronic® F68 (CMNPs-plur) to enhance their colloidal stability. The resulting material was dispersed in phosphate buffer solution at pH 7.4 to study the Doxorubicin loading. After shaking for 48 h, 99.13% of the drug was loaded by the nanocomposites. Subsequently, the drug release was studied in different working phosphate buffer solutions (i.e., PB pH 4.5, pH 6.0 and pH 7.4) to determine the efficiency of the synthesized material for drug delivery as pH-dependent drug nanocarrier. The results have shown a drug release quantity 18% higher in mimicking tumor environment than in the physiological one. Therefore, this study demonstrates the ability of CMNPs-plur to release a drug with pH dependence, which could be used in the future for the treatment of cancer "in situ" by means of controlled drug release.

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