Skeletal muscle ribosomal proteins: General characteristics and effect of diabetes

Abstract

1. 1. Skeletal muscle and liver ribosomes contained a similar, if not identical, heterogeneous group of basic proteins. The proteins had approx. 18 moles percent of acidic, and about 27 moles percent of basic residues; there were only small amounts of sulfur containing amino acids and of tryptophan. Alanine, glycine and serine accounted for most of the N-terminal amino acids, although there were also lesser amounts of valine, proline, methionine, aspartic acid and glutamic acid. 2. 2. The proteins of skeletal muscle ribosomes had great electrophoretic heterogeneity (there were at least 25 bands); the pattern of bands was, however, the same as with proteins from liver ribosomes. 3. 3. Each ribosome subunit from skeletal muscle contained a number of unique proteins; some of the subunit proteins had the same electrophoretic mobility. The pattern of the proteins from whole ribosomes was reconstituted when the 60-S and 40-S subunit proteins were combined and coelectrophoresed. From analysis of the subunits it appears that the minimum number of ribosomal proteins was 33. 4. 4. Diabetes did not produce a detectable alteration in the electrophoretic pattern of skeletal muscle ribosomal proteins.