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Amperometric assay of coenzyme‐dependent oxidoreductase enzymes in a flow‐through cell
Author(s) -
Wallace Thomas C.,
Leh Melonia Berezny,
Coughlin Robert W.
Publication year - 1977
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.260190609
Subject(s) - oxidoreductase , nad+ kinase , cofactor , enzyme , amperometry , chemistry , biochemistry , substrate (aquarium) , electrochemistry , chromatography , biology , electrode , ecology
We have demonstrated that a simple electrochemical cell can serve as a detector of NADH concentration in a flow system thereby providing an assay technique for NADH dependent enzymes. When this is applied to NADH produced by enzymatic reaction, then a reproducible measure of enzyme activity is obtained. This method of enzyme activity assay is applicable to a number of oxidoreductase enzymes which employ NAD + or NADP + as coenzymes to achieve substrate modification. The presence of electroactive species in samples of human serum has proved a serious problem in the electrochemical analysis of serum activity. These species produce a large background anode current at the anode voltage appropriate for NADH oxidation. The presence of this high current limits the usefulness of amplification of the current output to detect small changes in NADH concentration.