What does "S' mean in 18S or 28S RNA? - (Jul/31/2006 )

Hi all,

Eukaryotic ribosomes contain 4 different rRNA molecules: 5S, 5.8S, 18S and 28S. What does the "S" stand for and what does it mean? ?

Thanks!!

The S is an abbreviation for "Svedberg" the unit of molecular size named after the Nobel prize winner who developed methods of determining molecular size by centrifugation. It refers to the rate at which molecules sediment in centrifuges run at very high speed.

just browing, thanks phage434, was something interesting to know