Dolichol(C55) mono- and pyrophosphatases of the rat liver

Abstract
Dilichol mono- and pyrophosphatase (DPase and DPPase) activity [involved in glycoprotein synthesis] was studied in rat livers. The DPase activity in microsomes had a pH optimum of 6.5, was inhibited by NaF and had a specific activity 1/5 that of the pyrophosphatase. DPPase exhibited a pH optimum of 8.0 and was inhibited by bacitracin; the hydrolysis products were dolichol monophosphatase and orthophosphate. Both phosphatases displayed high specific activities in lysosomes and plasma membranes, and were present in microsomes and outer mitochondrial membranes, but appeared to be absent from mitochondrial inner membranes and peroxisomes.