ABSTRACT
A variety of considerations influence our choice of experimental conditions when attempting to observe Electron spin resonance (ESR) signals. The ESR signal is extremely sensitive to the nature of the environment surrounding the absorbing electrons. This is because local environmental conditions can alter the magnetic field encountered by the electrons. In the case of ESR, where the recorded signal is a derivative of the absorption curve, “linewidths” are approximated by the separation of the maximum upward and downward deflections of the ESR signal. Spin-level ESR studies of the interaction of the classes of compounds with target cells seems certain to enhance our understanding of the evolution and function of naturally occurring pesticides. Certain plant-produced compounds, of which rotenone is probably the best-known example, exert their effects on specific reactions, and the application of ESR to such systems should yield much information, particularly if the enzymes involved could be spin labeled.
