Table I. Kinetic parameters for aspartylation of yeast tRNA^Asp transcripts with yeast AspRS in the absence or presence of tobramycin.

ATP/MgCl2 (mM)	Inhibitortobramycin (mM)	Competitor tRNAtotal [mM]	Km (nM)	kcat (s–1)	kcat/Km (relative)	Loss of specificity (x-fold)
5/15a	0	–	44	0.66	1	1
5/15a	1	–	466	0.33	0.047	21
5/15a	2	–	945	0.38	0.027	37
5/15a	3	–	1190	0.30	0.017	60
5/15a	3	10	151	0.27	0.12	8
5/15a	3	30	115	0.21	0.12	8
5/15a	3	90	95	0.18	0.13	8
2/10b	0	–	732	0.31	0.028	35
2/10b	3	–	1285	0.58	0.03	33

^aATP:Mg²⁺ ratio of 1:3.

^bATP:Mg²⁺ ratio of 1:5.