Isolation and characterization of membrane proteins responsible for attachment of polyribosomes to rough microsomal fraction of rat liver.
A protein fraction which has a high affinity for polyribosomes was isolated from rough microsomal membranes of rat liver. The mode of polyribosome binding to this fraction (R-fraction) was studied by using CsCl equilibrium centrifugation and compared with that for stripped rough microsomal membranes. The following were found. (1) The polyribosome-binding cpacity of the R-fraction was heat-labile and sensitive to trypsin, and was suppressed by increasing KCl concentration and addition of 0.1 mM-aurintricarboxylic acid. (2) Of the four subfractions obtained by gel filtration of the R-fraction on a Sephadex G-200, only the R1-fraction, eluted at the void volume, showed a high affinity for polyribosomes. The polyribosome-binding capacity of the R1-fraction decreased with time on storage at 4 degrees C. (3) The R1-fraction contained three major proteins with mol. wts. 108,000, 99,000 and 65,000.
D000818:Animals; D001312:Aurintricarboxylic Acid / Q000494:pharmacology; D001665:Binding Sites / Q000187:drug effects; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D003840:Deoxycholic Acid; D004591:Electrophoresis, Polyacrylamide Gel; D008297:Male; D008565:Membrane Proteins / Q000302:isolation & purification* / Q000378:metabolism; D008862:Microsomes, Liver / Q000032:analysis*; D008970:Molecular Weight; D011092:Polyethylene Glycols; D011132:Polyribosomes / Q000032:analysis / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D012967:Sodium Dodecyl Sulfate
D008565:Membrane Proteins; D003840:Deoxycholic Acid; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D001312:Aurintricarboxylic Acid; D011189:Potassium Chloride