Release of GPI-anchored membrane aminopeptidase P by enzymes and detergents has some peculiarities

The enzyme aminopeptidase P (APP) of rat small intestine is an integral membrane protein. It is not released from the membrane by proteinases and is also resistant to bacterial inositol-specific phospholipases C (PI-PLC's). We show that this resistance is due to a hindered accessibility of the bond split by PI-PLC and not to a modified glycosylphosphatidyl inositol (GPI)-anchor.