Biol. Pharm. Bull. 29(8) 1771—1774 (2006)

molecular taxonomy based on the primary structures of common plant proteins, instead of so-called secondary metabolites. To evaluate the effectiveness of this concept, we carried out a series of studies on the family Solanaceae, using ferredoxin (Fd), an iron-sulfur electron-transfer protein. This protein was chosen for this study because it is easy to isolate and has an appropriate molecular weight for determining the primary structure. Previously, we reported the primary structures of Fds from 14 solanaceous plants and one leguminous plant. Our recent results have suggested that their amino acid sequences were related to their taxonomic position among plants that belong to the same genus or family, but not among plants in different families, although there may not be enough sequence data to reach any definite conclusions. It may be worthwhile to determine the amino acid sequences of Fds from many important medicinal plants that belong to diferent families. These considerations led us to elucidate the amino acid sequences of Fds from Panax ginseng (Araliaceae), the root of which is one of the most commonly used traditional medicines in China, Korea, and other Asian countries for the treatment of various diseases. In this report, we determined the primary structure of Fd from P. ginseng (Araliaceae), and compared it with those of Fds from other higher plants.