title: Probable occurrence of brain basic protein factor I, an activator of phosphoprotein phosphatases.
abstract: Basic protein factor I (BPFI was purified to homogeneity from bovine brain by boiling and trichloroacetic acid-precipitation of tissue homogenate, followed by DEAE-cellulose, Sephadex G-150, Affi-Gel-phenothiazine, and Bio-Gel P-6DG chromatographic procedures. The preparation appeared as a single protein band in the SDS-polyacrylamide gel electrophoresis with a minimal Mr of 13,200. The factor was a basic protein as indicated by an estimated isoelectric point of pH 8.3 and a high content of amino acids including arginine, histidine, lysine and others. In the absence of Mn2+, the factor stimulated the phosphoprotein phosphatases (PPase) from rabbit brains. Unlike histones or protamine, the factor was a poor substrate for megamodulin-dependent protein kinase. In addition, the factor did not interact significantly with E. coli megamodulin.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002352:Carrier Proteins / Q000378:metabolism; D002417:Cattle; D004789:Enzyme Activation; D004926:Escherichia coli / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000302:isolation & purification* / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; C050174:brain basic protein factor I; C015482:protein kinase modulator; D008345:Manganese; D010749:Phosphoprotein Phosphatases