Related Experiment Video
Updated: Jun 28, 2026
A Semi-High-Throughput Adaptation of the NADH-Coupled ATPase Assay for Screening Small Molecule Inhibitors
Published on: August 17, 2019
Amperometric determination of urea using an NADH-dependent coupled enzyme
1Department of Chemistry, University of New Orleans, New Orleans, LA 70148, U.S.A.
Abstract:
Enzyme electrodes for the amperometric measurement of urea were prepared by co-immobilizing l-glutamate dehydrogenase and urease onto an Immobilon-AV affinity membrane with attachment to a glassy carbon electrode. Reduced nicotinamide adenine dinucleotide (NADH) was used as the electroactive species. The electrochemical oxidation of NADH was monitored at +1.0 V vs. Ag/AgCl. The enzyme immobilized electrode was linear over the range of 2.0 x 10(-5) to 2 x 10(-4)M. The response time of the electrode was 3 min and the optimum pH of enzyme immobilized membrane was pH 7.4-7.6 (Dulbecco's buffer solution). It was stable for at least two weeks and 50 assays. There were no interferences from other physiological material, except for high levels of ascorbic acid.
Related Concept Videos
01:10Amperometry: Overview
01:23Urea Cycle
01:20Titration of a Weak Base with a Strong Acid
Using the ICE table and substituting the Kb value, we calculate the initial pH of 50 mL of 0.1 M ammonia to be 11.11. Addition of 25 mL of 0.1 M hydrochloric acid to this solution of ammonia results in a buffer with an equal concentration of ammonia and ammonium ions. The pH of this buffer can be calculated by substituting these...