yield of plasma membrane , banding in the 25 % percoll ( d = 1.051 ) , was high as judged by the recoveries of the marker enzymes , 5'-nucleotidase ( 58.0 +/- 5.4 % , n = 5 ) , alkaline phosphatase ( 46.0 +/- 3.0 % , n = 4 ) and mg2+-stimulated neutral sphingomyelinase ( 48.0 +/- 4.2 % , n = 3 ) ;
C0007603
plasma membrane
C3539580
neutral sphingomyelinase