Stimulation of phosphatidylethanolamine exchange by castor bean cytosol proteins.

Cytosol proteins prepared from castor bean endosperm (4-day-old) seedlings stimulate the exchange of [(3)H]phosphatidylethanolamine between liposomes and mitochondria. The acceleration of the exchange depends on the quantity of cytosol proteins, the time of incubation, and the respective amounts of liposomes and mitochondria. On a per seedling basis, the active proteins are essentially located in the endosperm, whereas the roots and the cotyledons are less rich in these proteins.