Inhibits the enzymatic activity of all phospholipase A2 tested, binding them 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. N-glycosylated, probably by biantennary structure. Glycosylation does not change PLA2 inhibitory activity. Belongs to the CNF-like-inhibitor family.