Turnover of protein-bound phosphorylserine in membrane preparations from ox brain catalysed by intrinsic kinase and phosphatase activity.
1. The turnover of protein-bound phosphorylserine in preparations of membrane fragments from ox brain cortex was studied. 2. Turnover was considered to arise from the action of intrinsic protein kinases and phosphatases on a membrane protein or proteins. 3. Properties of the kinase system were studied by measuring the rate of incorporation of (32)P from gamma-labelled ATP into protein-bound phosphorylserine isolated from partial acid hydrolysates of membrane proteins. 4. Properties of the phosphatase system were studied by observing the rate of loss of (32)P from membrane preparations pre-labelled with [(32)P]ATP. 5. Net phosphorylation and dephosphorylation of membrane protein was observed during incubation of membrane preparations with and without ATP. 6. The rate of turnover was about 4nmol of P/h per mg of protein at 20 degrees C; dephosphorylation was considered to be the rate-limiting step.
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism*; D004586:Electrophoresis; D066298:In Vitro Techniques; D007454:Iodides / Q000378:metabolism; D007700:Kinetics; D010710:Phosphates / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010759:Phosphorus Isotopes; D010770:Phosphotransferases / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism; D012694:Serine / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D013997:Time Factors
D007454:Iodides; D010710:Phosphates; D010759:Phosphorus Isotopes; D011506:Proteins; D012965:Sodium Chloride; D012694:Serine; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; D010744:Phosphoric Monoester Hydrolases