Identification of the 32 kDa components of bovine lens EDTA-extractable protein as endonexins I and II.
EDTA-extractable protein (EEP) is a mixture of major lens membrane proteins with molecular masses ranging from 32 kDa to 40 kDa. These bind to the lens membrane in a Ca2(+)-dependent manner. In the present study we have identified and purified two distinct 32 kDa components of EEP (designated as EEP 32-1 and EEP 32-2) from bovine lens that inhibit phospholipase A2 activity. Both EEP 32-1 and EEP 32-2 bind to phospholipid-containing liposomes and actin filaments in a Ca2(+)-dependent fashion. Immunochemical studies and two-dimensional electrophoreses demonstrate that the two proteins are distinct from one another. Both EEP 32-1 and EEP 32-2 are clearly different from calpactin (lipocortin) or its proteolytic fragments because they did not react with anti-[human placenta calpactin (lipocortin)] antibody. Our results also indicate that EEP 32-1 is very similar to endonexin I and that EEP 32-2 corresponds to endonexin II.
Kobayashi
R
R
Department of Biochemistry, Akita University School of Medicine, Japan.
Nakayama
R
R
Ohta
A
A
Sakai
F
F
Sakuragi
S
S
Tashima
Y
Y
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017304:Annexin A5; D002135:Calcium-Binding Proteins / Q000276:immunology / Q000302:isolation & purification*; D002417:Cattle; D002850:Chromatography, Gel; D003429:Cross Reactions; D004492:Edetic Acid; D015180:Electrophoresis, Gel, Two-Dimensional; D007908:Lens, Crystalline / Q000032:analysis*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010741:Phospholipases A / Q000037:antagonists & inhibitors; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism
D000199:Actins; D017304:Annexin A5; D002135:Calcium-Binding Proteins; D010743:Phospholipids; D004492:Edetic Acid; D010741:Phospholipases A; D054467:Phospholipases A2