Localization of enzymes involved in polyphosphoinositids metabolism on the cytoplasmic surface of the human erythrocyte membrane.
1. Impermeable inside-out and right-side-out vesicles were prepared from membranes of human erythrocytes. During preparation of each kind of impermeable vesicle, permeable vesicles were also obtained. 2. Incubation of vesicles with [gamma-32P]ATP at 37 degrees C for periods of up to 1 hr did not change the topography or the permeability of the vesicles. 3. Vesicles incorporated labeled phosphate from [gamma-32P]ATP into both diphosphoinositide and triphosphoinositide, but impermeable inside-out vesicles incorporated significantly more nuclide than did right-side-out vesicles. 4. Permeable vesicles derived during the preparation of inside-out vesicles were as active as impermeable inside-out vesicles in the incorporation of labeled phosphate into the polyphosphoinositides. However, permeable vesicles derived during the preparation of right-side out vesicles were not as active. 5. Impermeable right-side-out vesicles, treated with 0.01 percent saponin, incorporated labeled phosphate into the polyphosphoinositides at a level comparable to that of impermeable inside-out vesicles. 6. These data show that the enzymes involved in metabolism of diphosphoinositide and triphosphoinositide are located on the cytoplasmic surface of the erythrocyte membrane.
D000110:Acetylcholinesterase / Q000097:blood; D000255:Adenosine Triphosphate / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D004912:Erythrocytes / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000097:blood; D006801:Humans; D010716:Phosphatidylinositols / Q000097:blood*; D011092:Polyethylene Glycols; D013997:Time Factors
D010716:Phosphatidylinositols; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D000110:Acetylcholinesterase