Nucleic Acids Research, 2001, Vol. 29, No. 17 3652-3656
© 2001 Oxford University Press
Characterization of a multi-functional metal-mediated nuclease by MALDI-TOF mass spectrometry
Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA and 1Bruker Daltonics, Inc., 47697 Westinghouse Drive, Fremont, CA 94539, USA
Mass spectrometric analysis of reaction products allows simultaneous characterization of activities mediated by multifunctional enzymes. By use of MALDI-TOF mass spectrometry, the relative influence of magnesium and manganese promoted exonuclease and phosphatase activities of Esherichia coli exonuclease III have been quantitatively measured, offering a rapid and sensitive alternative to radioactivity quantification and gel electrophoresis procedures for determination of reaction rate constants. Manganese is found to promote higher levels of exonuclease activity, which could be a source of mutagenic effects if this ion were selected as the natural cofactor. Several potential applications of these methods to quantitative studies of DNA repair chemistry are also described.
* To whom correspondence should be addressed. Tel: +1 614 292 2703; Fax: +1 614 292 1685; Email: cowan{at}chemistry.ohio-state.edu Present address: Uraiwan Puapaiboon, LumiCyte, Inc., 48480 LakeView Boulevard, Fremont, CA 94538, USA