Purification and Characterization of a Novel Plasma Membrane Phosphatidate Phosphohydrolase from Rat Liver

摘要: Abstract An N-ethylmaleimide-insensitive phosphatidate phosphohydrolase, which also hydrolyzes lysophosphatidate, was isolated from the plasma membranes of rat liver. The specific activity an anionic form enzyme (53 kDa, pI < 4) increased 2700-fold. A cationic (51 = 9) purified to homogeneity, but -fold purification low because highly unstable. Immunoprecipitating antibodies raised against homogeneous protein confirmed identity as phosphohydrolase and were used identify enzyme. Both forms are integral membrane glycoproteins that converted 28-kDa proteins upon treatment with N-glycanase F. Treatment neuraminidase allowed it be in same manner yielded immunoreactive a molecular mass identical protein. Thus, two ionic most likely represent different sialated states 51-53-kDa detected liver, heart, kidney, skeletal muscle, testis, brain. Little thymus, spleen, adipose, or lung tissue. This work provides tools for determining regulation function signal transduction cell activation.