Studies on the half life time of rat liver transfer RNA species

Abstract
The tRNA fraction, extracted from very high speed supernatant fluid, from livers of rats injected with 3H‐orotic acid, attained maximum specific activity after a little over 24 hr and, thereafter, decayed with an apparent half life of 5 days. This behaviour of tRNA was indistinguishable from that of liver rRNA and the acid soluble pool. Chromatography of tRNA, doubly labelled during a period of short synthesis and of prolonged decay, on a BD cellulose column, indicated that individual tRNA species turn over at a constant rate with respect to one another.