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ARS Home » Midwest Area » West Lafayette, Indiana » National Soil Erosion Research Laboratory » Research » Publications at this Location » Publication #234014
Title: Soil oxidoreductases and FDA hydrolysis

Author
item PROSSER, JENNIFER - Institute Of Environmental Science And Research
item SPEIR, TOM - Institute Of Environmental Science And Research
item Stott, Diane

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/8/2010
Publication Date: 10/1/2011
Citation: Prosser, J.A., Speir, T.W., Stott, D.E. 2011. Soil oxidoreductases and FDA hydrolysis. In: R.P. Dick (Ed.), Methods of SOil Enzymology, Soil Science society of America, Madison, WI. p. 103-124.

Interpretive Summary:

Technical Abstract: The oxidoreductases (E.C. 1.) comprise the largest enzyme group and consist of enzymes that catalyze reactions between two compounds, one of which is oxidized (the donor) while reducing the other (the acceptor) (Dixon and Webb, 1979). In common with all redox reactions, the reaction mechanism involves electron transfer, expressed in a simplistic representation as: A- + B ' A + B-. However, the observed reaction usually involves the transfer of two hydrogen atoms from the donor to the acceptor (dehydrogenation) and, consequently, most of the enzymes are called dehydrogenases. The entire dehydrogenase catalyzed reaction takes place in an enzyme-donor-acceptor complex and does not involve ions or electrons reacting in solution (Dixon and Webb, 1979). Where molecular oxygen is the acceptor, the enzymes are termed oxidases and the O2 is reduced to water. Here again, the reaction mechanism is not straightforward, and may involve the transfer of one or two H atoms (or one or two electrons) to the O2. For one particular oxidase enzyme, laccase, which catalyzes a one-electron transfer, it appears that the enzyme may operate like a battery, storing electrons from individual oxidation reactions in order to reduce molecular oxygen, intermediates of which remain bound to the enzyme complex (Thurston, 1994). One or both oxygen atoms from O2 can also be incorporated into the substrate being oxidized and the enzymes that catalyze these transformations all fall into E.C. 1.13. and 1.14. and are termed oxygenases. There are many other oxidoreductase acceptors, including hydrogen peroxide (H2O2), which acts as both donor and acceptor for the enzyme catalase, and as acceptor for peroxidases. As an alternative for an indicator of overall microbial activity in soil, we propose the use of an assay for fluorescein diacetate (FDA) hydrolysis.