The Svedberg (S) value of eukaryotic ribosomes is:
Sedimentation coefficient measured in Svedberg units depends on molecular weight, density and shape, not strictly additive, so sum of subunit S values does not equal particle S value. Cytoplasmic ribosomes of eukaryotes consist of forty S small subunit containing eighteen S rRNA and approximately thirty three proteins and sixty S large subunit containing twenty eight S, five point eight S and five S rRNA plus about forty seven proteins, together associating into eighty S monosome of three point two megadaltons and about twenty five nanometers diameter when translating. Prokaryotic ribosomes ar
Ref: Warner Cell Biol; eukaryotic 80S 40S+60S not additive, distinct from bacterial 70S.
