Potato galactolipase treatment of spinach chloroplasts were investigated. The enzyme reaction was inhibited with Mg<Cl>___2, bovine serum albumin and sucrose, to varying levels with their specific action on the chloroplast grana stacking. The reaction increased in three steps with increase of temperature, suggesting that there are different localization and existing forms of lipids. By the enzyme treatment and subsequent centrifugation on density-gradient column, lipid-depleted chloroplasts were prepared. Analysis revealed that the preparation retained nearly half portion of the intial electron flows, but H^+ uptake and phosphorylation activities were completely lost.