Inhibits the enzymatic activity of all phospholipase A2 tested, binding with micromole to nanomole affinity. Optimum pH is 4-12. Important decrease in activity at pH 2. Optimum temperature is 4-90 degrees Celsius. Weak decrease in activity at 100 degrees Celsius. Heterotrimer of 2 subunits A and 1 subunit B; non-covalently linked. Secreted in blood plasma. Expressed by the liver. Belongs to the CNF-like-inhibitor family.