Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An optical array biosensor encapsulated with hydrolase and oxidoreductase using sol-gel immobilization technique has been fabricated for simultaneous analysis and screening of multiple samples to determine the presence of multianalytes which are clinically important in relation to renal failure. Urease and creatinine deiminase were used to detect urea and creatinine, while glucose oxidase and uricase were coimmobilized with horseradish peroxidase to quantify glucose and uric acid. Moreover, the concentrations of analytes in fetal calf serum were measured and quantified using the developed sensing system. The array biosensor showed good specificity for the simultaneous analysis of multiple samples for multianalytes without obvious cross-interference. The analytical ranges of the four analytes were between 0.01 and 10mM with detection limits of 2.5-80 microM. High precision with relative standard deviations of 3.8-9.2% (n=45) was also demonstrated. The reproducibility of array-to-array in 3 consecutive months was 5.4% (n=3). Moreover, the concentrations of analytes in fetal calf serum were 5.9 mM for urea, 0.13 mM for creatinine, 3.3mM for glucose, and 0.15 mM for uric acid, which were in good agreement with results obtained using the traditional spectroscopic methods. These results demonstrate the first use of a sol-gel-derived optical array biosensor for simultaneous analysis of multiple samples for the presence of multiple clinically important renal analytes.
...
PMID:Simultaneous determination of renal clinical analytes in serum using hydrolase- and oxidase-encapsulated optical array biosensors. 1546 67

An intracellular uricase from Bacillus fastidious A.T.C.C. 26904 was characterized and evaluated for serum uric acid assay by a patented kinetic uricase method. The active uricase was 151 kDa by gel filtration through Sephadex G-200. Both SDS/PAGE and matrix-assisted laser-desorption ionization-time-of-flight MS resolved a single polypeptide with a molecular mass of approx. 36.0 kDa. The N-terminal sequence was AERTMFYGKGDV. The optimum pH for this uricase ranged from 9.0 to 10.5. At pH 9.2, the Km (Michaelis-Menten constant) was 204+/-14 micromol/l (n=8) and the Ki (inhibition constant) for xanthine was 41+/-7 micromol/l (n=5). By analysing the data monitored within 5 min at 0.03 unit/ml uricase, this kinetic uricase method gave linear response to uric acid in reaction solution from 1.3 to 60 micromol/l. Aside from other common errors, 30 micromol/l xanthine in the reaction solution caused no error in this kinetic uricase method, while it caused negative error in the indirect equilibrium method by peroxidase-coupled assay of H2O2. Uric acid in clinical sera by this kinetic uricase method (Ck) closely and positively correlated with that from the indirect equilibrium method (Ce) (Ck = 0.008+1.081 x Ce, r>0.990, n=99). However, Bland-Altman analysis suggested inconsistency between Ck and Ce. These results indicated that this kinetic uricase method using this uricase was reliable for serum uric acid assay with enhanced resistance to xanthine besides other common errors.
...
PMID:Characterization of a uricase from Bacillus fastidious A.T.C.C. 26904 and its application to serum uric acid assay by a patented kinetic uricase method. 1668 79

The carbon nanotube modified biosensors for respectively monitoring uric acid (UA) and total cholesterol in blood were studied. The transducers were based on two screen-printed carbon electrodes, a carbon working electrode and a reference electrode. For UA sensors, uricase was immobilized on the surface of electrodes together with potassium ferrocyanide as electron transfer mediator. For cholesterol sensors, the corresponding enzyme system consists of cholesterol esterase, cholesterol oxidase, peroxidase and potassium ferrocyanide. Multi-wall carbon nanotubes (MWNTs) and single-wall carbon nanotubes (SWNTs) were applied to prompt electron transfer. Experimental results showed that the carbon nanotube modified biosensors offers a reliable calibration profile and stable electrochemical properties. The calibration graphs were linear up to 200mg/L UA and 400mg/dL cholesterol.
...
PMID:Study of carbon nanotube modified biosensors for monitoring uric acid and total cholesterol in blood. 1728 61

Uric acid (UA) is determined using the UV-vis molecular absorption properties of peroxidase (HRP). The method as a whole involves UA oxidation in the presence of uricase (UOx), giving H(2)O(2.) The H(2)O(2) then reacts with HRP forming the compound I species which returns to its initial form by reaction with UA and intramolecular reduction. The molecular absorption changes of HRP at 420nm during the reaction enable the UA to be determined. A mathematical model relating the analytical signal to UA, UOx and HRP has been developed and experimentally validated. The possibility of carrying out both enzymatic reactions sequentially or simultaneously is discussed, the latter option producing better analytical performances. The method permits UA determination in the range 1.5x10(-6)-4.0x10(-5)M, with an R.S.D. of about 3% (n=5, 1.5x10(-6)M UA). It has been applied to analyte determination in synthetic serum samples.
...
PMID:Uric acid determination using uricase and the autotransducer molecular absorption properties of peroxidase. 1819 Aug 10

In most medical facilities in Japan, either uricase-catalase or uricase-peroxidase method has been adopted as a sensitive determination of serum uric acid concentration. However, the values obtained from the same patients at different time points are often variable with those methods. Accelerated generation of uric acid and impaired excretion in the kidney are promoted by several dietary factors, such as foods with higher content of sugars (fructose and xylitol), fat and purine bases, and by alcohol consumption, starvation and dehydration. In contrast, hyperglycemia and excess salt ingestion are conductive to accelerate urate excretion. Physicians should notice representative factors fluctuating serum uric acid levels as described above.
...
PMID:[How do we set the standard value of serum uric acid levels?]. 1840 22

Hyperuricemia contributes to the pathomechanism of diseases such as renal failure, gout, tumor lysis syndrome and metabolic syndrome. Tumor lysis syndrome is a complication of malignancies caused by massive tumor cell lysis due to either spontaneous tumor cell lysis or to different therapies and it may cause hyperuricemia. Recently, for treatment of hyperuricemia the recombinant urate oxidase (rasburicase) therapy has been used. This enzyme converts uric acid with high affinity into soluble allantoin which is eliminated by the kidneys. In this reaction high concentration of hydrogen peroxide is generated. This hydrogen peroxide could cause hemolysis and especially methemoglobin formation, in case of glucose-6-phosphate-dehydrogenase and catalase deficiencies. Therefore it is recommended that these enzymes are determined before therapy. For monitoring of rasburicase therapy the determination of serum uric acid concentration is used. More than 95 per cent of Hungarian clinical laboratories are using the uricate oxidase/peroxidase reactions and hydrogen peroxide measurements in the uric acid assays. These assays may be interfered by ascorbic acid and hydrogen peroxide which is generated by rasburicase either in vivo or in vitro.
...
PMID:[Rasburicase therapy may cause hydrogen peroxide shock]. 1870 12

A reagentless uric acid selective biosensor constructed by immobilising uricase and horseradish peroxidase (HRP) in carbon paste without the addition of an electron transfer mediator is described. The response of the electrode is based on the enzymatic reduction of hydrogen peroxide in the presence of uric acid. Uricase and HRP were dispersed in the carbon paste and the optimum paste mixture was determined. Poly(o-aminophenol) was electropolymerised at the working surface area of the electrode acting as a conducting polymer layer. Cyclic voltammetry was used to characterise the permselective characteristics of the polymer layer. At an applied potential of 50 mV vs. Ag/AgCl, a linear response was obtained up to 1 x 10(-4) M, with a limit of detection of 3 x 10(-6) M. The sensor had a response time of 37 s. a calibration precision of 2.2% (n = 4) and an estimated sample frequency of 20 h(-1). Responses to the analyte of interest were pH dependent. The sensor was incorporated into a flow injection system for the qualification of uric acid in human serum. Results compared favourably with a standard spectrophotometric method.
...
PMID:Poly(o-aminophenol)-modified bienzyme carbon paste electrode for the detection of uric acid. 1896 49

A new amperometric biosensor based on urate oxidase-peroxidase coupled enzyme system for the specific and selective determination of uric acid in urine was developed. Commercially available urate oxidase and peroxidase were immobilized with gelatin by using glutaraldehyde and fixed on a pretreated teflon membrane. The method is based on generation of H(2)O(2) from urine uric acid by urate oxidase and its consuming by peroxidase and then measurement of the decreasing of dissolved oxygen concentration by the biosensor. The biosensor response depends linearly on uric acid concentration between 0.1 and 0.5 muM. In the optimization studies of the biosensor, phosphate buffer (pH 7.5; 50 mM) and 35 degrees C were obtained as the optimum working conditions. In addition, the most suitable enzyme activities were found as 64.9x10(-3) U cm(-2) for urate oxidase and 512.7 U cm(-2) for peroxidase. And also some characteristic studies of the biosensor such as reproducibility, substrate specificity and storage stability were carried out.
...
PMID:A biosensor based on urate oxidase-peroxidase coupled enzyme system for uric acid determination in urine. 1896 64

The response characteristics of various carbon substrates towards the direct oxidative measurement of urate and other key purine biomarkers have been compared. A novel carbon fibre laminate assembly has been proposed as an alternative substrate for the preparation of disposable sensing strips. The fabrication method is generic and readily transferable to a number of sensor applications. Its performance in the determination of urate within biofluids (serum and plasma) has been critically assessed. An inter-laboratory pilot study demonstrated the bioanalytical efficacy of the approach with the responses validated through comparison with the standard colorimetric (uricase/peroxidase) assay.
...
PMID:A clinical assessment of direct electrochemical urate measurements. 1897 Apr 86

An intracellular uricase from Bacillus fastidiosus with high catalytic capacity and strong resistance to xanthine was inactivated in water but could be essentially re-activated in solutions of high ionic strength. By polyacrylamide gel electrophoresis (PAGE), gradient PAGE, sodium-dodecyl-sulfate-PAGE, gel-filtration through Sephadex G200, and activity staining with peroxidase and its chromatogenic substrate, this homotetrameric uricase in water was found to dissociate into inactive homodimers that could form active homotetramers again in solutions of high ionic strength. Sensitivity to low ionic strength of solutions complicates formulation of this uricase as a drug and its elimination requires protein engineering.
...
PMID:Reversible inactivation of an intracellular uricase from Bacillus fastidiosus via dissociation of homotetramer into homodimers in solutions of low ionic strength. 1973 51


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---