title: Purification and characterization of the major 50-kDa repressor protein from cytoplasmic mRNP of rabbit reticulocytes.
abstract: A 50-kDa protein has been purified to homogeneity from free mRNP of rabbit reticulocytes. This protein, designated as p50, is present within both free mRNP (approximately 4 mol protein/mol globin mRNA) and polyribosomal mRNP (approximately 2 mol protein/mol globin mRNA). p50 is a basic protein (pI approximately 9.5) and is characterized by a high glycine content of approximately 20%. Nitrocellulose-filter analysis has shown that p50 interacts with globin mRNA with an association constant of approximately 2.5 x 10(8) M-1 (100 mM KAc, 4 degrees C). Various RNA and polyribonucleotides have the following relative affinity for p50; poly(G) > poly(U) > globin mRNA approximately 16S rRNA > poly(A) > poly(C). p50 can be phosphorylated both in vitro and in vivo.
authors: Institute of Protein Research, Russian Academy of Sciences, Pushchino.
authors: W B
authors: WB
authors: Minich
authors: I P
authors: IP
authors: Maidebura
authors: L P
authors: LP
authors: Ovchinnikov
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002458:Cell Fractionation; D003593:Cytoplasm / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005914:Globins / Q000096:biosynthesis / Q000235:genetics; D008970:Molecular Weight; D010766:Phosphorylation; D011132:Polyribosomes / Q000378:metabolism / Q000648:ultrastructure; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D012097:Repressor Proteins / Q000097:blood* / Q000302:isolation & purification; D012156:Reticulocytes / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000097:blood* / Q000302:isolation & purification; D012270:Ribosomes / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000596:Amino Acids; D012333:RNA, Messenger; D012097:Repressor Proteins; D012261:Ribonucleoproteins; C026452:messenger ribonucleoprotein; D005914:Globins