urease was immobilized on platinum electrode both by chemical binding and electropolymerization.the conductometric urea biosensor thus prepared showed a detection limit of 4.9×10-5 m and linear dynamic range from 4.9×10-5 to 5.8×10-3 m for urea concentration when the enzyme is covalently immobilized on pt electrodes. conductometric transducers respond to the changes in ionic strength thereby le...

In this study, urease was isolated from Cicer arietinum and immobilized in calcium alginate beads. Various parameters, such as effect of thermal stability, temperature, optimum pH and pH stability, substrate concentration, reuse and storage stability were investigated and the results of the investigation were compared with the soluble enzyme. The activity yield of immobilization was calculated ...

Urease (urea amidohydrolase, EC 3.5.1.5), widely distributed in nature, catalyzes the hydrolysis of urea to ammonia and carbon dioxide at a rate 1014 times faster than the uncatalyzed reaction.1–3 Among enzymes, urease is most extensively studied for immobilization due to the possible exploitation in practical applications, such as quantitative determination of blood urea in clinical examinatio...

In this work, a glutathione (GSH) modified gold microelectrode was used for the covalent immobilization of urease biomolecules via the glutaraldehyde-coupling agent. The self-assembled monolayers (SAMs) onto the gold surface was investigated by using the electrochemical impedance spectroscopy measurements (EIS). Before urease grafting, a significant interaction was noticed between urea and the ...

Background: Immobilization is an approach in industry to improve stability and reusability of urease. The efficiency of this technique depends on the type of membrane and the method of stabilization. Methods: The PEI-modified egg shell membrane was used to immobilize urease by absorption and glutaraldehyde cross-linking methods. The membranes were characterized by Fourier-transform infrared sp...

The role of microbial urease in calcite precipitation was studied utilizing a recombinant Escherichia coli HB101 containing a plasmid, pBU11, that encodes Bacillus pasteurii urease. The calcite precipitation by E. coli HB101 (pBU11) was significant although its precipitation level was not as high as that by B. pasteurii. Addition of low concentrations (5-100 microM) of nickel, the cofactor of u...

A novel method for the rapid modification of fullerene for subsequent enzyme attachment to create a potentiometric biosensor is presented. Urease was immobilized onto the modified fullerene nanomaterial. The modified fullerene-immobilized urease (C60-urease) bioconjugate has been confirmed to catalyze the hydrolysis of urea in solution. The biomaterial was then deposited on a screen-printed ele...

An original and novel assay system with urease as a catalyst and CdSe/ZnS quantum dots (QDs) as an indicator has been developed for quantitative analysis of urea. By mixing urease and QDs, the determination of urea can be performed in a quantitative manner. The detection is based on the enhancement of QD photoluminescence (PL) intensity, which is correlated to the enzymatic degradation of urea....