Abstract
Intravenous injection of heparin into the trout resulted in the appearance in the plasma of a lipase with the properties of lipoprotein lipase. The enzyme was purified to apparent electrophoretic homogeneity by means of heparin--Sepharose affinity chromatography. The enzyme was eluted with 1.5 M-NaCl and had a specific activity approx. 450-fold that of the post-heparin plasma. The activity of the purified enzyme was inhibited by 1.0 M-NaCl and protamine sulphate and stimulated between 3- and 8.8-fold by the addition of trout plasma. The activity was strongly stimulated by trout very low density lipoproteins and to a lesser extent by high density lipoproteins. The isolated enzyme fraction gave a single band on sodium dodecyl sulphate/polyacylamide-gel electrophoresis and had an apparent subunit M sub(r) of 63,000. These results suggest that the uptake of lipid by the tissues in the trout can occur by a process similar to that in mammals.