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Kinetically controlled urease electrode
Author(s) -
Hamann H.,
Scheller F.,
Kühn M.
Publication year - 1989
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140010610
Subject(s) - urease , cellulose triacetate , electrode , urea , chemistry , michaelis–menten kinetics , chromatography , cellulose , inorganic chemistry , enzyme , enzyme assay , biochemistry
The parameters and the measuring principle of a urease electrode are described. The urease is physically entrapped in cellulose triacetate on the active surface of a pH glass electrode with an internal reference electrode. The Michaelis constant of immobilized urease was similar to that of soluble enzyme (K M = 2.40 mmol/L). The average apparent enzyme activity amounts to 2 IU per sensor preparation. An enzyme loading factor of 0.04 was determined. It indicates kinetically controlled reaction conditions of the sensor. A fixed‐time measuring procedure provides a response time of 30 seconds and a linear response within a concentration range of 2 to 40 mmol/L urea in real biological samples (e.g., serum).