Rapid purification of two lipocortin-like proteins from mice lung

We have purified two proteins (40 kDa and 36 kDa) from mice lung by the method of calcium-precipitation/EGTA solubilization and then a separation on a high anion exchanger column (Mono Q HR 5/5. Pharmacia) with a gradient of NaCl. The two proteins were strong inhibitors of phospholipase A2 as assessed in vitro with porcine pancreatic phospholipase A2 and 3H]-oleic acid labeled E. Coli membranes as substrate. The 40 kDa protein had a pI of 5.8 and was found to be immunologically related to human recombinant lipocortin I. The 36 kDa protein had a pI of 4.7 and cross-reacted with a polyclonal antibody raised against a 32 kDa human lipocortin-like protein described in human blood mononuclear cells. We report here a rapid purification of two distinct lipocortin-like proteins from mice lung.