scholarly journals Enzymic determination of inorganic phosphates, organic phosphates and phosphate-liberating enzymes by use of nucleoside phosphorylase-xanthine oxidase (dehydrogenase)-coupled reactions

1985 ◽  
Vol 230 (1) ◽  
pp. 255-260 ◽  
Author(s):  
H de Groot ◽  
H de Groot ◽  
T Noll
Keyword(s):  
Uric Acid ◽  
Xanthine Oxidase ◽  
High Sensitivity ◽  
Inorganic Pyrophosphatase ◽  
Enzyme Assays ◽  
Tetrazolium Salt ◽  
Nucleoside Phosphorylase ◽  
Organic Phosphates ◽  
Inorganic Phosphates

Coupled enzyme assays are described for measuring inorganic phosphates, organic phosphates and phosphate-liberating enzymes in biological material. The assays all determine Pi by its reaction with inosine, catalysed by nucleoside phosphorylase; this yields ribose 1-phosphate and hypoxanthine. The hypoxanthine is oxidized to uric acid by xanthine oxidase, and may be measured either by the absorbance of the uric acid, or by the formazan formed when a tetrazolium salt is used as the oxidant. The coupled enzyme assays are characterized by high sensitivity, quantitative utilization of phosphates and stoichiometric formation of the measurable products, measurement at pH 6.0-8.5, determination of phosphates within a single analytical step, and continuous measurement of phosphohydrolase activity in a corresponding rate assay. Examples include determinations of substrates such as Pi, PPi and AMP, and of enzymes such as 5′-nucleotidase, inorganic pyrophosphatase and glucose-6-phosphatase. Directions for further examples are given.

Fluorometric determination of uric acid in bovine milk

2010 ◽  
Vol 77 (4) ◽  
pp. 438-444 ◽  
Author(s):  
Torben Larsen ◽  
Kasey M Moyes
Keyword(s):  
Heat Treatment ◽  
Uric Acid ◽  
Xanthine Oxidase ◽  
Bovine Milk ◽  
Oxidase Inhibitor ◽  
Enzymatic Oxidation ◽  
Fast Method ◽  
Xanthine Oxidase Inhibitor ◽  
Milk Samples

The primary objective of this study is to validate a new fast method for determination of uric acid in milk. The method is based on an enzymatic-fluorometric technique that requires minimal pre-treatment of milk samples. The present determination of uric acid is based on the enzymatic oxidation of uric acid to 5-hydroxyisourate via uricase where the liberated hydrogen peroxide reacts with 10-acetyl-3,7-dihydroxyphenoxazine via peroxidase and the fluorescent product, resorufin, is measured fluorometrically. Fresh composite milk samples (n=1,072) were collected from both Jersey (n=38) and Danish Holstein (n=106) cows from one local herd. The average inter- and intra-assay variations were 7·1% and 3·0%, respectively. Percent recovery averaged 103·4, 107·0 and 107·5% for samples spiked with 20, 40 or 60 μmof standard, respectively, with a correlation (r=0·98;P<0·001) observed between the observed and expected uric acid concentrations. A positive correlation (r=0·96;P<0·001) was observed between uric acid concentrations using the present method and a reference assay. Storage at 4°C for 24 h resulted in lower (P<0·01) uric acid concentrations in milk when compared with no storage or samples stored at −18°C for 24 h. Addition of either allopurinol (a xanthine oxidase inhibitor) or dimethylsulfoxide (a solvent for allopurinol) did not affect milk uric acid concentrations (P=0·96) and may indicate that heat treatment before storage and analysis was sufficient to degrade xanthine oxidase activity in milk. No relationship was observed between milk uric acid and milk yield and milk components. Authors recommend a single heat treatment (82°C for 10 min) followed by either an immediate analysis of fresh milk samples or storage at −18°C until further analysis.

Sensitive electrochemical determination of dopamine and uric acid using AuNPs(EDAS)–rGO nanocomposites

2016 ◽  
Vol 8 (22) ◽  
pp. 4379-4390 ◽  
Author(s):  
Victor Vinoth ◽  
Jerry J. Wu ◽  
Sambandam Anandan
Keyword(s):  
Uric Acid ◽  
High Sensitivity ◽  
Electrochemical Determination ◽  
Synthesis Process ◽  
Potential Candidate ◽  
Sonochemical Synthesis ◽  
One Step ◽  
Sensing Application ◽  
Electro Catalytic Activity

AuNPs(EDAS) – rGO nanocomposites were prepared by a facile one step sonochemical synthesis process. Here, EDAS acts as an interlinker for anchoring gold on rGO and it also acts both as a reducing agent and a stabilizing agent. The AuNPs(EDAS) – rGO nanocomposites show excellent electro-catalytic activity towards oxidation of DA and UA. The AuNPs(EDAS) – rGO nanocomposites exhibit low detection limits, high sensitivity, it could be a potential candidate for sensing application and in biosensor technology in the future.

Nanocomposite based on restacked crystallites of β-NiS and Ppy for the determination of theophylline and uric acid on screen-printed electrodes

2019 ◽  
Vol 43 (48) ◽  
pp. 19397-19407
Author(s):  
P. Muthukumaran ◽  
R. Ramya ◽  
P. Thivya ◽  
J. Wilson ◽  
G. Ravi
Keyword(s):  
Uric Acid ◽  
Electrocatalytic Activity ◽  
High Sensitivity ◽  
Screen Printed Electrodes ◽  
Screen Printed

We synthesized calcinated β-NiS with a highly crystalline porous nature and mixed it with Ppy to prepare a nanocomposite, which exhibited high electrocatalytic activity and this was then used to detect theophylline and uric acid with high sensitivity and stability.

scholarly journals Three-Dimensional Au/Holey-Graphene as Efficient Electrochemical Interface for Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 84 ◽  
Author(s):  
Aihua Jing ◽  
Gaofeng Liang ◽  
Yixin Yuan ◽  
Wenpo Feng
Keyword(s):  
Electron Microscopy ◽  
Ascorbic Acid ◽  
Uric Acid ◽  
Graphene Oxide ◽  
Composite Structures ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Cyclic Voltammograms ◽  
Brain Physiology

The quantification of ascorbic acid (AA), dopamine (DA), and uric acid (UA) has been an important area of research, as these molecules’ determination directly corresponds to the diagnosis and control of diseases of nerve and brain physiology. In our research, graphene oxide (GO) with nano pores deposited with gold nanoparticles were self-assembled to form three-dimensional (3D) Au/holey-graphene oxide (Au/HGO) composite structures. The as-prepared 3DAu/HGO composite structures were characterized for their structures by X-ray diffraction, Raman spectrum, scanning electron microscopy, and transmission electron microscopy coupled with cyclic voltammograms. Finally, the proposed 3DAu/HGO displayed high sensitivity, excellent electron transport properties, and selectivity for the simultaneous electrochemical determination of AA, DA and UA with linear response ranges of 1.0–500 μM, 0.01–50 μM and 0.05–50 μM respectively. This finding paves the way for graphene applications as a biosensor for detecting three analytes in human serum.

A naphthalimide-based novel “Turn-On” fluorescence approach for the determination of uric acid and monitoring of xanthine oxidase activity

2019 ◽  
Vol 11 (32) ◽  
pp. 4190-4196 ◽  
Author(s):  
Jagpreet Singh Sidhu ◽  
Shilpa Sharma ◽  
Ashutosh Singh ◽  
Neha Garg ◽  
Navneet Kaur ◽  
...  
Keyword(s):  
Uric Acid ◽  
Xanthine Oxidase ◽  
Oxidase Activity ◽  
Fluorescence Emission ◽  
Turn On ◽  
Xanthine Oxidase Activity

Fluorescence emission of the receptor enhanced upon its binding with uric acid due to the cancellation of the PET phenomenon.

scholarly journals Carbon Black-Carbon Nanotube Co-Doped Polyimide Sensors for Simultaneous Determination of Ascorbic Acid, Uric Acid, and Dopamine

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1691 ◽  
Author(s):  
Yue Wang ◽  
Tian Yang ◽  
Yasushi Hasebe ◽  
Zhiqiang Zhang ◽  
Dongping Tao
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Carbon Nanotube ◽  
Carbon Black ◽  
Simultaneous Determination ◽  
Simultaneous Detection ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Co Doped

Carbon black (CB) and carbon nanotube (CNT) co-doped polyimide (PI) modified glassy carbon electrode (CB-CNT/PI/GCE) was first prepared for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The CB-CNT/PI/GCE exhibited persistent electrochemical behavior and excellent catalytic activities. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used for the simultaneous detection of AA, DA, and UA in their ternary mixture. The peak separations between AA and DA, and DA and UA, are up to 166 mV and 148 mV, respectively. The CB-CNT/PI/GCE exhibited high sensitivity to DA and UA, with the detection limit of 1.9 µM and 3 µM, respectively. In addition, the CB-CNT/PI/GCE showed sufficient selectivity and long-term stability, and was applicable to detect AA, DA, and UA in human urine sample.

Simultaneous determination of ascorbic acid, dopamine and uric acid at a nitrogen-doped carbon nanofiber modified electrode

RSC Advances ◽  
2015 ◽  
Vol 5 (16) ◽  
pp. 11925-11932 ◽  
Author(s):  
Jinying Sun ◽  
Libo Li ◽  
Xueping Zhang ◽  
Dong Liu ◽  
Simin Lv ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Carbon Nanofiber ◽  
Simultaneous Detection ◽  
High Sensitivity ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon ◽  
Small Biomolecules ◽  
Excellent Stability

This paper demonstrates high electrocatalytic activity of NCNF/GCE towards small biomolecules. The proposed electrochemical sensor exhibits good selectivity, high sensitivity and excellent stability towards AA, DA and UA simultaneous detection.

Fluorescence enhancement detection of uric acid based on water-soluble 3-mercaptopropionic acid-capped core/shell ZnS:Cu/ZnS

RSC Advances ◽  
2014 ◽  
Vol 4 (48) ◽  
pp. 25183-25188 ◽  
Author(s):  
Meihua Wang ◽  
Weifen Niu ◽  
Xin Wu ◽  
Lixia Li ◽  
Jun Yang ◽  
...  
Keyword(s):  
Uric Acid ◽  
Fluorescence Enhancement ◽  
High Sensitivity ◽  
Water Soluble ◽  
Core Shell ◽  
Lower Toxicity ◽  
Real Samples ◽  
Mercaptopropionic Acid

A simple core/shell ZnS:Cu/ZnS QD based fluorescence enhancement system is constructed for detecting uric acid. The method with high sensitivity, selectivity and lower toxicity features was applied for determination of UA in real samples.

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