PH-Dependent conversion of liver-membranous alkaline phosphatase to a serum-soluble form by [formula omitted]-butanol extraction

Abstract

Alkaline phosphatase released from rat liver plasma membrane under usual conditions was electrophoretically not identical with a soluble form in serum which was derived from the liver. The liver-membranous alkaline phosphatase, however, was converted to the serum-soluble form when the liver plasma membrane was treated with n -butanol under the acidic conditions lower than pH 6.5. Such pH-dependent conversion of the enzyme was not observed in plasma membrane of rat ascites heaptoma AH-130 cells. The converting activity for alkaline phosphatase was detected not only in plasma membrane but also in lysosomal membrane of rat liver.