title: Enzyme transfer of phosphate from adenosine triphosphate to protein-bound serine residues in cerebral microsomes.
abstract: 1. Microsomes from guinea-pig brain grey matter were incubated with [(32)P]ATP at 3mm concentration and the phosphate bound to the acid-washed, lipid-free residue was determined. 2. The binding process was Mg(2+)-dependent and resulted in the transfer of about 1-2 mmumoles of phosphate/mg. of protein/min. Under the conditions used univalent cations (Na(+),K(+) and Li(+)) inhibited the binding. 3. An unspecified proportion of this bound phosphate could be recovered in protein-derived phosphorylserine. The yield of labelled phosphorylserine was also decreased by univalent cations. 4. The bound phosphate formed with 3mm-MgATP was stable; addition of Na(+) or K(+) ions to the already labelled preparation had no effect on the bound phosphate level. 5. Bound phosphate was also formed when a solubilized fraction of the microsomes was incubated with ATP; univalent cations also inhibited this process. 6. p-Chloromercuribenzoate reduced the binding by about 25%; the inhibition was restored by cysteine.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D002729:Chloromercuribenzoates / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008861:Microsomes / Q000201:enzymology* / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D010710:Phosphates / Q000378:metabolism*; D010759:Phosphorus Isotopes; D011485:Protein Binding; D012694:Serine
chemical_list: D002729:Chloromercuribenzoates; D009419:Nerve Tissue Proteins; D010710:Phosphates; D010759:Phosphorus Isotopes; D012694:Serine; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases