Electron Spin Resonance of Adenosine Triphosphate

Abstract

IT has been suggested that in adenosine triphosphate (ATP) the phosphate chain and the adenine are linked by the pentose, so that the two terminal phosphates touch the two nitrogen atoms at positions 6 and 7 in the adenine ring¹; and that, since triphosphate compounds might be electron acceptors and adenine is a good electron donor, the adenine group might donate an electron to the triphosphate group². I. Isenberg and A. Szent-Györgyi² obtained an electron spin resonance signal from ATP (di-sodium salt) which they attributed to internal charge transfer between the adenine and the triphosphate. They also suggested that there was a possibility that the signal could be due to a transition metal impurity in the form of a transition metal – ATP complex. In view of the great importance of ATP in living processes, we have re-examined the electron spin resonance of this compound to decide between these possibilities.