Table I. EF2 and sordarin binding to 80S ribosomes.

	Background	80S	EF2	80S + EF2
Sordarin (pmol)	0.2	0.2	0.9	2.3
v	–	–	–	0.58

In a total volume of 50 µl, 5 pmol of 80S ribosomes and 51 pmol of EF2 were incubated in the presence of [³H]sordarin (20 µM, f.c.). Controls were performed using only sordarin, 80S ribosomes and sordarin, or EF2 and sordarin. After the binding reaction (see Materials and methods) the sample was passed through a PD10 gel filtration column. The amount of sordarin present in the flow-through was determined by measuring the radioactivity in the flow-through. The occupancy v (pmol sordarin/pmol 80S ribosomes) was calculated taking the value of EF2 + sordarin as the background value and taking into account that only 2.4 pmol of 80S were present in the flow-through.