Differences in the release of 5'-nucleotidase and alkaline phosphatase from plasma membrane of several cell types by PI-PLC

1. We have compared the effect of phosphatidyl inositol specific phospholipase C (PI-PLC) on the attachment of both 5'-nucleotidase and alkaline phosphatase to the liver plasma membrane from different species. 2. Our results demonstrate differences in the susceptibilities of both enzymes to PI-PLC treatment in relation to their origin. 3. These results were confirmed by immunoblotting using polyclonal anti-5'-nucleotidase antibodies. 4. In addition, in a single animal, susceptibility of both enzymes to PI-PLC treatment is different from one tissue to another. 5. The different percentages of released enzymes could be explained either by a polymorphism in the anchoring of these proteins at the cell surface membrane, or by a different steric hindrance or environment at the cleavage site itself.