Appearance of lipoprotein lipase activity in human non-postheparin serum

Through comparison of serum and citrate-plasma samples from full blood let from human subjects not having received any previous heparin-treatment it has been demonstrated that the activity figures of serum lipoprotein lipase exceed those of the plasma. The serum enzyme has been identified by its substrate specificity, albumin requirement, by the effect of heparin, moreover by the protamin and salt inhibition. Our results are interpreted on the basis that the labile lipoprotein lipase activity present in sera is due to the activation during blood-coagulation of the latent enzyme in circulation.