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Catalytic buffers enable positive‐response inhibition‐based sensing of nerve agents
Author(s) -
Russell Alan J.,
Erbeldinger Markus,
DeFrank Joseph J.,
Kaar Joel,
Drevon Geraldine
Publication year - 2001
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10152
Subject(s) - urease , chemistry , paraoxon , hydrolysis , urea , catalysis , enzyme , base (topology) , chromatography , biochemistry , acetylcholinesterase , mathematical analysis , mathematics
We report herein an efficient method to control pH in reactions catalyzed by hydrolytic enzymes, such as the degradation of paraoxon by phosphotriesterase (E.G. 3.1.8.1; OPH), using urease‐catalyzed (E.G. 3.5.1.5) urea hydrolysis as a buffering agent. Given the distinct pH profiles of urease and OPH activities, urease produces base on demand in response to pH drop during paraoxon detoxification. As pH changes, the enzyme activities fluctuate to finally stabilize at a pH “set‐point,” where the rates of acid and base generation are equal. By varying the urease to OPH ratio, various pH “set‐points” ranging between 6.5 and 8.5 were achieved within minutes and could be predicted theoretically. This dynamic approach for pH control was successfully applied to the development of a positive‐response inhibition‐based sensor. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 352–357, 2002.