CARBOHYDRATE-BINDING PROTEINS IN BOVINE KIDNEY HAVE CONSENSUS AMINO-ACID-SEQUENCES OF ANNEXIN FAMILY PROTEINS

Ca2+-dependent carbohydrate-binding proteins were purified from bovine kidney extracts. Upon SDS-polyacrylamide gel electrophoresis under nonreducing conditions, the purified fraction gave doublet protein bands corresponding to 33 kDa (p33) and 41 kDa (p41). Under reducing conditions, a single protein band (p33) was observed. p33 and p41 were submitted to proteolytic digestion with endoproteinase Lys-C, the peptides produced were separated by reversed-phase high performance liquid chromatography, and their amino acid sequences were determined by an automated gas-phase protein sequenator. Most of the resulting partial amino acid sequences of these proteins were strikingly homologous to annexin IV, an annexin family protein, i.e. Ca2+/phospholipid-binding proteins, especially in the consensus sequences. In the presence of Ca2+, both proteins bound to vesicles composed of phosphatidylserine and phosphatidylethanolamine, but not phosphatidylcholine. These results indicated that p33 and p41 are members of annexin family proteins.