Table 1.

Rates of [³⁵S]-fMet release mediated by E. coli RF1 and RF2 from E. coli 70S ribosomes programmed with canonical or pseudouridylated stop codons.

	Stop codon
	UAA	UAG	ΨAA	ΨAG	AAA	no mRNA
	kobs, s−1
10 nM RF1	0.031 ± 0.004	0.039 ± 0.005	0.032 ± 0.005	0.028 ± 0.004	(1.7 ± 0.2) ·10−5	(9.1 ± 1.0)·10−6
30 nM RF1	0.045 ± 0.004	not measured	0.044 ± 0.005	not measured	(2.8 ± 0.3)·10−5	(1.7 ± 0.3)·10−5
100 nM RF1	0.058 ± 0.008	0.046 ± 0.005	0.052 ± 0.006	0.048 ± 0.005	(7.9 ± 0.6)·10−5	(2.5 ± 0.2)·10−5
500 nM RF1	0.055 ± 0.006	0.059 ± 0.006	0.066 ± 0.008	0.059 ± 0.006	(1.8 ± 0.1)·10−4	(4.2 ± 0.1)·10−5
10 nM RF2	(5.5 ± 0.8)·10−4	not measured	(5.7 ± 1.0)·10−4	not measured	not measured	not measured
25 nM RF2	(4.9 ± 1.0)·10−4	not measured	(5.9 ± 0.7)·10−4	not measured	not measured	not measured
2 μM RF2	(4.3 ± 0.3)·10−4	not measured	(5.4 ± 0.4)·10−4	not measured	(1.2 ± 0.2)·10−5	(6.0 ± 1.9)·10−6
T. th. 70S + 500 nM E. coli RF1	0.023 ± 0.002	not measured	0.020 ± 0.003	not measured	not measured	not measured