Involved in lipid catabolism. Essential for sterol esters biosynthesis in leaves and seeds, but not in flowers. Plays a role in controlling the free sterol content of leaves. Catalyzes the transacylation of acyl groups from phospholipids to a variety of different sterols. Prefers phosphatidylethanolamine over phosphatidylcholine as an acyl donor. Not active toward neutral lipids. Highly specific for position sn-2, which in plant lipids is essentially devoid of saturated acyl groups. Broad sterol specificity (cholesterol > campesterol > sitosterol > stigmasterol), but no activity with lupeol or beta-amyrin. By senescence. Early leaf senescence. Strong reduction in total sterol esters content in leaves and seeds. No change in flowers. Belongs to the AB hydrolase superfamily. Lipase family.