Electron transfer (ET) is an important elementary step of chemical reaction.Phosphorus is the center of energy expression in biological system. As a result, the research on the ET of phosphoryl and nonphosphoryl peptides is very important for us to understand the role of phosphorus in life and reveal the secrets of life. In this paper, the ET in some phosphoryl and nonphosphoryl peptides are studied by ESR. It is observed that the electron transfers along the backbone of the peptide and that phosphoryl group takes part in the elementary process in the phosphoryl peptide first.
