Lipase evolution: trout, Xenopus and chicken have lipoprotein lipase and apolipoprotein C-II-like activity but lack hepatic lipase-like activity.

Lipoprotein lipase and hepatic lipase are members of a gene family which also contains pancreatic lipase. High activity of lipoprotein lipase is present in extrahepatic tissues in all mammals studied and also in birds. The activity of hepatic lipase varies more. To investigate the evolutionary relationship, lipase activities in tissues of some lower vertebrates were measured. In fish and in frog, low activities with the characteristics of lipoprotein lipase were found. Serum from frog and from fish, and plasma from chicken, stimulated lipoprotein lipase in vitro, indicating that these species contain analogues to human apolipoprotein C-II. Little or no hepatic lipase-like activity was found in post-heparin plasma or in liver homogenates of chickens. In fish liver, lipase activity with an apparent heparin affinity similar to, or even higher than lipoprotein lipase was found. Frog liver contained a small amount of lipase activity with high heparin affinity. This activity was inhibited both by apolipoprotein C-II and by 1 M NaCl. It is not clear whether the low lipase activities in livers from fish and from frog are variants of hepatic lipase. Since lipoprotein lipase and apolipoprotein C-II are already present in fish, this lipase probably evolved before hepatic lipase.