[Various characteristics of the protein composition of ribosomes separated from granular membranes of the endoplasmic reticulum of rat liver].

New data on protein composition of endoplasmic reticulum membranes are obtained by PAAG electrophoresis using DS-Na detergent. In preparations of proteins separated from membranes of liver and spleen ribosomes as well as of rat liver after inhibition of protein synthesis by ethionine there were found three additional lacking in free ribosomes of protein fractions with molecular mass 50, 150 and 170 kDa. Their relative content decreases due to isolation of membranes and ribosomes in the medium with high ionic strength as well as due to additional purification using gel-filtration. The mentioned proteins are supposed to belong to the endoplasmic reticulum membranes and not to be organospecific.