No abstract

Complete isolation of Fraction I protein from alfalfa leaves was achieved by a combi nation of ammonium sulfate fractionation and gel filtration. Analytical ultracentrifugation gave a _??_, w value of 18.0. Judging from the CD spectrum the protein contains a large amount of ƒÀ-form as well as tobacco F-I protein. Electron micrographs showed closely similar appearances for the two F-1 proteins. The F-1 protein (from alfalfa leaves) was separated to large subunits (53,000 daltons) and small subunits (14,000 daltons) on SDS gel electro phoresis. Further the amino acid composition of the large subunit was found similar to those of tobacco and spinach, but considerably different from them in small subunits.