STRUCTURAL HETEROGENEITY OF PHOSPHOLIPASE-D IN 10 DICOTS

The occurrence of multiple forms of phospholipase D (EC 3.1.4.4) was i nvestigated in different tissues of castor bean (Ricinus communis) and in other plant species. Phospholipase D variants were resolved by non denaturing and isoelectric focusing polyacrylamide gel electrophoresis and detected by immunoblotting using anti-phospholipase D antibodies and by enzyme activity assay. Three phospholipase D variants were prod uced differentially in the roots, endosperm, cotyledons, and hypocotyl of 5-day postgermination seedlings of castor bean. Furthermore, diffe rent patterns of phospholipase D variants were found in the different regions of hypocotyl (elongated and hook). Multiple phospholipase D fo rms were found in florets of cauliflower and broccoli, leaves of cabba ge, celery, tomato, and potato, and alfalfa sprouts, suggesting that s tructural heterogeneity of phospholipase D occurs widely in plants. (C ) 1996 Academic Press, Inc.