The mechanism of the increase in the activity of liver alkaline phosphatase in experimental cholestasis: measurement of an increased enzyme concentration by immunochemical titration.

Alkaline phosphatase (EC 3.1.3.1) activity increases 5-15 fold in the livers of rats, following bile duct ligation. The mechanism of this increase has been the subject of numerous investigations. In HeLa cells the synthesis of a different phosphatase enzyme protein with higher catalytic activity has been postulated. After preparing an antiserum against rat liver phosphatase, we compared the phosphatase protein concentration in normal and cholestatic livers by immunochemical titration. Our results clearly indicate that the elevation of enzyme activity is due to an increased accumulation of enzyme protein.