Preparation of photosystem I particles from spinach by column chromatography.

Photosystem I (PS I) particles were prepared from spinach leaves by a method which includes two different types of chromatographies: an ion-exchange DEAE-Toyopearl column and a hydrophobic Butyl-Toyopearl column. Potassium ferricyanide was added to the preparation media in the early steps of preparation. The addition of ferricyanide protected iron-sulfur centers from damage due to photoinactivation during preparation and preserved some unknown polypeptides on the isolated PS I. Consequently, the PS I particles isolated by the present method showed a very high activity in the NADP-photoreduction of 388 μmol NADP reduced/mg Chl/hr.