Nuclear Magnetic Resonance Methods of Monitoring Cell Metabolism

Nuclear magnetic resonance (NMR), which was discovered in 1946, was used primarily by organic chemists for elucidation of the structure of relatively small organic molecules. The advent of Fourier transform NMR, coupled with the development of superconducting magnets with higher field strengths, opened the technique to a variety of biological and clinical applications. NMR is now a proven technique for monitoring metabolism in diverse systems—isolated cells and perfused organs, as well as the intact animal and humans (1 –4 ). Great scope exists, therefore, for the development of NMR applications in the biotechnology industry. A major analytical advantage of NMR spectroscopy is its unique ability to yield extensive information on a wide range of biologically important low-molecular-weight species simultaneously. Although many NMR-detectable nuclei exist, studies of cell metabolism have generally utilized the ³¹ P, ¹³ C, ¹ H, and ¹⁵ N nuclei (1 ,4 ). The basic principles of NMR spectroscopy, which are beyond the scope of this chapter, have been described extensively elsewhere (for example, see ref. 5 ). This chapter will focus on various NMR-based approaches for studying metabolism in cultured mammalian cells (including lines used by the biotechnology industry) and will highlight commonly used techniques for obtaining preparations of cells suitable for NMR studies.