Diisopropylfluorophosphate Is Not a Specific Label for the Red Cell Membrane

When red cells were labeled either in vitro or in vivo with DF³²P, the label was attached primarily at intracellular, not membrane, sites. Thus, despite the fact that it binds to and inactivates the red cell membrane enzyme, acetylcholinesterate, DF³²P is not a specific label for the red cell membrane.