title: A protein kinase C inhibitory activity is present in rat brain homogenate.
abstract: The partial purification and characterization of (a) factor(s) from rat brain which inhibit(s) the activity of calcium and phospholipid-dependent protein kinase from the same tissue is described. This factor, present in 100 000 X g rat brain homogenate supernatant, is inactivated upon treatment by trypsin and pepsin and is therefore assumed to be a protein. It was partially purified by ion-exchange chromatography on DEAE-cellulose, ammonium sulfate precipitation and gel filtration. This inhibitor is not stable to heating at 70 degrees C for 10 min, however partial renaturation of the inhibitory activity can be observed after incubation of the denatured inhibitor for 24 h at 4 degrees C. It is precipitable by 10% trichloroacetic acid and by 2 M ammonium sulfate. It exhibits a Stokes radius of 20 A by gel exclusion chromatography, corresponding to a molecular mass of 20 kDa assuming a globular shape. Kinetic analysis of the inhibition of calcium-phospholipid-dependent histone kinase activity indicates that the inhibitor is competitive with respect to the protein substrate. No change was observed in the kinetic values of the kinase for ATP, Ca2+ and phospholipids.
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000032:analysis*; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004791:Enzyme Inhibitors / Q000032:analysis*; D006657:Histones / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D010766:Phosphorylation; D011493:Protein Kinase C; D047428:Protein Kinase Inhibitors; D051381:Rats; D011919:Rats, Inbred Strains; D014357:Trypsin / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D047428:Protein Kinase Inhibitors; C015482:protein kinase modulator; D011493:Protein Kinase C; D014357:Trypsin