AN ESTERASE NEOSYNTHESIZED IN POST-GERMINATED SUNFLOWER SEEDS IS RELATED TO A NEW FAMILY OF LIPOLYTIC ENZYMES

We previously carried out the purification and biochemical characteriz ation of an acylester hydrolase from post-germinated sunflower, (Helia nthus annuus L.) seeds. Here we establish that the 18 N-terminal resid ues of its sequence contain the GDSL consensus motif recently describe d in five bacterial lipolytic enzymes thought to constitute a differen t group from the classical lipases and esterases. Using purified speci fic polyclonal antibodies we demonstrate that the occurence of fatty a cyl-ester hydrolase activity in post-germinated seeds is due to a de n ovo synthesis of the protein. Sunflower-seed esterase is the first GDS L enzyme to have been characterized in plants.