Annexin A8
calcium-dependent phospholipid binding
Vascular anticoagulant beta: a novel human Ca2+/phospholipid binding protein that inhibits coagulation and phospholipase A2 activity. Its molecular cloning, expression and comparison with VAC-alpha.
A cDNA was cloned coding for a new member of the human Ca2+-modulated phospholipid-binding protein family termed annexins. Due to its 56% identity to the human vascular anticoagulant (VAC) the new protein is named VAC-beta, renaming the previous VAC as VAC-alpha. Northern analysis detects one hybridizing mRNA species of 2.2 kb in human placenta. Genomic Southern blot analysis shows a VAC-beta gene of comparable complexity to the VAC-alpha gene. The cDNA was expressed in Escherichia coli and the recombinant protein purified to homogeneity. Antiserum raised against VAC-beta weakly cross-reacts with VAC-alpha. The properties of VAC-beta as an anticoagulant and as an inhibitor of phospholipase A2 activity were analyzed and compared to those of VAC-alpha.