Effect of Magnesium Chelation on the 31P NMR Spectra of ATP: An Undergraduate Biochemistry Laboratory Experiment

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 10 Issue 5 (2005) pp 359-362

Effect of Magnesium Chelation on the ³¹P NMR Spectra of ATP: An Undergraduate Biochemistry Laboratory Experiment

Michael O. Hurst* and Jeffrey A. Orvis

Department of Chemistry, Georgia Southern University, Statesboro, GA 30460 hurstmo@GeorgiaSouthern.edu
Received June 7, 2004. Accepted February 27, 2005.

Published online: 16 September 2005

Abstract. ³¹P NMR spectra of 100 mM solutions of ATP in 100 mM Tris buffer, pH 7.4, were measured with various concentrations of magnesium ion in order to develop an undergraduate biochemistry laboratory illustrating how magnesium binding effects the ATP phosphates. A downfield shift of 95.55 ppm was observed for the b-phosphate peak at 200 mM magnesium when compared to the spectrum of ATP without added magnesium, as well as a shift of 52.4 ppm for the g-phosphate, and a small upfield shift of 15.4 ppm for the a-phosphate. A ³¹P NMR spectrum of ATP under the same conditions with 50 mM calcium ion instead of magnesium ion showed b-, g-, and a-phosphate downfield shifts of 69.36, 30.83, and 6.16 ppm, respectively. The significance of the chelations on the role of Mg⁺² in ATP enzymology is discussed.

Key Words: Laboratories and Demonstrations; quantitative analysis; absorption spectroscopy

(*) Corresponding author. (E-mail: hurstmo@GeorgiaSouthern.edu)

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New file posted 11/8/05

Tables 1 and 2 have been corrected and the abstract has been amended.