Table 2.

Kinetic parameters for aminoacylation of yeast tRNA^Gly by GlyRS variants

GlyRS variant	Unfractionated yeast tRNA			In vitro-transcribed yeast tRNAnGly
	Km (μM)	kcat (s−1)	kcat/Km (M−1 s−1)	Km (μM)	kcat (s−1)	kcat/Km (M−1 s−1)
GlyRS1	0.33 ± 0.03	0.38 ± 0.15	11.4 × 105	0.28 ± 0.03	0.33 ± 0.03	12.3 × 105
GlyRS1(ΔIP)	0.89 ± 0.39	0.08 ± 0.01	1.0 × 105	1.37 ± 0.23	0.19 ± 0.02	1.4 × 105
GlyRS1(ΔKM)	0.91 ± 0.45	0.05 ± 0.02	0.5 × 105	NDa	ND	ND
GlyRS1(KMM1)	0.65 ± 0.13	0.08 ± 0.03	1.2 × 105	ND	ND	ND
GlyRS2	0.53 ± 0.08	0.10 ± 0.02	1.8 × 105	0.73 ± 0.27	0.15 ± 0.03	2.2 × 105

^aND, not determined.