PURIFICATION OF ACTIVE ESCHERICHIA-COLI RIBOSOME RECYCLING FACTOR (RRF) FROM AN OSMO-REGULATED EXPRESSION SYSTEM

Ribosome release factor (RRF) from Escherichia coli was overproduced f rom an osmo-expression vector. More than 40% of cell protein was RRF a fter 6 h of induction. A purification scheme is described that produce d 50 mg of RRF from an initial culture of 2 L. The recycling time for ribosomes synthesising the tripeptide fMet-Phe-Leu in vitro in the abs ence of RF3 was reduced from 40 to 15 s by the addition of purified 1. 5 mu M RRF.