Protein-bound phosphorylserine in acid hydrolysates of brain tissue. The determination of ( 32 P)phosphorylserine by ion-exchange chromatography and electrophoresis.
1. Partial acid hydrolysates of proteins derived from cortical slices of guinea-pig brain were divided into two parts and fractionated by ion-exchange chromatography and high-voltage electrophoresis. 2. The apparent yield of protein-bound phosphorylserine by the ion-exchange method was about three times that obtained by electrophoresis. 3. The specific radioactivity of phosphorylserine isolated from (32)P-labelled slices by electrophoresis was twice that isolated by chromatography. 4. The discrepancies were found to be due to the presence of unlabelled phosphates of unknown composition in the ;phosphorylserine' fraction obtained by the ion-exchange method. 5. Electrical stimulation of slices respiring in the presence of [(32)P]phosphate increased the specific radioactivity of the total phosphate in the chromatographic ;phosphorylserine' fraction by 53+/-11%, as compared with only 19+/-5% for the phosphorylserine isolated by electrophoresis.
D000818:Animals; D001923:Brain Chemistry; D002852:Chromatography, Ion Exchange; D004558:Electric Stimulation; D004586:Electrophoresis; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D066298:In Vitro Techniques; D010710:Phosphates / Q000032:analysis*; D010759:Phosphorus Isotopes; D011485:Protein Binding; D012694:Serine / Q000032:analysis*
D010710:Phosphates; D010759:Phosphorus Isotopes; D012694:Serine