Table 1. Editing efficiency of 3′ end mutants of tRNA^Val.

tRNAVal variant	Relative rate of ATP hydrolysisa	Relative aminoacylation efficiencyb (Vmax/Km)
Wild-type	(1.0)	(1.0)
A76→U76	–0.03c	0.39
A76→C76	–0.10c	0.50
A76→G76	–0.03c	0.0
C75→U75	0.76	0.31
C75→A75	0.87	0.42
C75→G75	0.04	0.01
C74→U74	0.93	0.33
C74→A74	0.98	0.86
C74→G74	0.81	1.1
A73→U73	0.85	0.31
A73→C73	0.89	0.44
A73→G73	0.07	0.026
tRNAVal(-CCA)	–0.01	ndd
tRNAVal(-ACCA)	–0.01	nd
No tRNA	–0.09	nd

^aNegative values are the result of small changes in the background rate of ATP hydrolysis.

^bResults are from Liu and Horowitz (29); included for comparison.

^cResults are from Tardif et al. (6); included for comparison.

^dnd, no detectable aminoacylation.