抄録
Esterase and lipase activities were determined with tributyrin and Ediol as substrate, respectively. Both activities were released into the blood by intravenous injection of heparin. The postheparin esterase and lipase (clearing factor lipase, CFL) activities were not separated from each other by gel filtration on Sephadex G-200 and Sepharose 4B.
CFL was purified 2, 000-fold by a modification of the method of Fielding. It catalyzed the hydrolysis of tributyrin as well as that of Ediol. The activity ratio of lipase to esterase of the preparation after Sephadex G-200 filtration was the same as that of purified CFL. Tributyrin competitively inhibited the hydrolysis of Ediol by the preparation after Sephadex G-200 filtration and by purified CFL. The esterase activity observed after heparin injection was eliminated by the antibody to CFL whereas that before heparin injection was not. The esterase activity after heparin injection was inhibited by sodium chloride as much as CFL activity.
From these results it was concluded that CFL catalyzes the hydrolysis of glycerides of both short- and long-chain fatty acids, and that the increase in the esterase activity in the plasma after heparin injection is caused by the esterase activity of CFL.
