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Identification of calcium‐dependent phospholipid‐binding proteins in higher plant cells
Author(s) -
Boustead Catherine M.,
Smallwood Margaret,
Small Hazel,
Bowles Dianna J.,
Walker John H.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80582-4
Subject(s) - phospholipid , phosphatidylserine , phosphatidylcholine , isoelectric point , biochemistry , calcium , annexin , liposome , antiserum , calcium binding protein , annexin a2 , chemistry , gel electrophoresis , biology , microbiology and biotechnology , antibody , in vitro , membrane , organic chemistry , immunology , enzyme
Calcium‐dependent phospholipid‐binding proteins of apparent M r 33 000 and 35 000 were isolated from suspension cultures of tomato cells. Two‐dimensional gel electrophoresis showed the proteins to have isoelectric points of approx. 5.7 and 5.6, respectively. In the presence of calcium, both proteins bound to liposomes formed from a mixture of phosphatidylserine and phosphatidylcholine, but not to liposomes of phosphatidylcholine alone. Both proteins showed immunological similarities to previously characterized calcium‐dependent phospholipid‐binding proteins (annexins) from Torpedo marmorata and mammalian species. The protein of M r 33 000 cross‐reacted with three separate antisera raised to the annexin Torpedo calelectrin, whereas that of M r 35 000 cross‐reacted with antisera to the bovine annexins p68 and p32/34. We suggest that the two proteins may represent the first identification in higher plants of the annexin family of calcium‐dependent phospholipid‐binding proteins.