Table 1.

pH dependence of k_pep for different aminoacyl-tRNAs at 20 °C

Aminoacyl-tRNA	*		(s-1)	(s-1) †
Asn-tRNAAsn	6.8	5.9 ± 0.2	11 ± 1	11 ± 1
Phe-tRNAPhe	7.2	6.1 ± 0.1	28 ± 1	27 ± 1
Ile-tRNAIle	7.8	6.1 ± 0.2	22 ± 1	21 ± 1
Ala-tRNAAla	7.9	6.3 ± 0.1	25 ± 2	24 ± 1
Gly-tRNAGly	7.8	7.36 ± 0.04	13 ± 1	7.6 ± 0.2
Pro-tRNAPro	8.6	7.8 ± 0.2	17 ± 5	6.0 ± 0.5

^*pK_a of the α-NH₂ group of aa-tRNA in bulk water (see Materials and Methods).

^†k_pep, calculated at pH 7.5 from fits of experimental data (Fig. 3 B–G).