Plant seed oils which are stored in cotyledons and embryos from small discrete intracellular particles called oil bodies. An oil body has a matrix of TAG, which is surrounded by a layer composed of phospholipids and proteins termed oleosins. In order to investigate the phycicochemcal and biochemical properties of oil bodies, the isolated and purified oil bodies were prepared from native soybean by the methods of flotation centrifugation, and then they were provided for the following experiments. Oil bodies were considerably stable at neutral pH and at less than 100℃. The surface active agents used here except sodium dodecyl sulfate did not decompose d the oil bodies. Thus, an oil body structure was indicated that the surface of the membrane was occupied by oleosins behind which there existed phospholipids. On the other hand, lipase broke the oil bodies and hydrolyzed triacylglycerol in them. Trypsin hydrolyzed partially the surface protein of the oil body, but the particle from of the oil body was maintained further. Lipase has been reported to hydrolyze the triacylglycerol in oil bodies during seed germination. The in vivo lipase reaction was reappeared in vitro in this investigation. It seems that oleosins, oil body membrane proteins, would be necessary to maitain the oil body structure and would play an important role in the lipase reaction.
Key words: Oilbody; oleosin; lipase.