60 KD POLYPEPTIDE OF CELL-WALL ACID-PHOSPHATASE FROM TOBACCO CELLS

The native cell wall acid phosphatase (APase), WP-II, of tobacco XD-6 cells was purified by chromatographic procedures. The purified WP-II y ielded one major band of M-r of 60 kD on SDS-polyacrylamide gel electr ophoresis(PAGE) after SDS treatment at 100 degrees C for 5 min. The pr eparation, however, yielded an additional smear band with M-r of 120 k D that retained phosphatase activity after the treatment with SDS at 2 0 degrees C for 3 hr. Two dimensional SDS-PAGE with different denatura tion suggested that the 120 kD band consisted of the 60 kD polypeptide . Renaturation of the 60 kD polypeptide recovered about 30% of the act ivity of the crude WP-II and 8% of that of the purified WP-II, respect ively. (C) 1998 Elsevier Science Ltd. All rights reserved.