TABLE 3.

Kinetic parameters for point mutated tRNA transcripts

The relative V_max/K_m for the T. thermophilus wild-type tRNA^Phe transcript was expressed as 100%. ND means that the kinetic parameters could not be calculated correctly.

Transcript name	Mutation site	Km	Vmax	Relative Vmax/Km or relative initial velocity
		nm	μmol mg−1 h−1	%
T. thermophilus wild-type tRNAPhe	None	130 ± 20	360 ± 60	100
Transcript 27	46G→A	110 ± 20	340 ± 60	110
Transcript 28	54U→A	130 ± 30	440 ± 70	125
Transcript 29	55U→A	ND	ND	<5a
Transcript 30	56C→G	ND	ND	Not detectable
Transcript 31	57G→C	ND	ND	<10a
Transcript 32	58A→G	ND	ND	Not detectable
Transcript 33	59U→C	ND	ND	<5a
Transcript 34	60U→C	ND	ND	<5a
Transcript 35	54U→G	120 ± 20	480 ± 80	150
Transcript 36	54U→C	130 ± 40	250 ± 60	80
Transcript 37	55U→G	100 ± 20	380 ± 80	135
Transcript 38	55U→C	120 ± 20	390 ± 70	120
Transcript 39	56C→U	ND	ND	Not detectable
Transcript 40	56C→A	ND	ND	Not detectable
Transcript 41	57G→A	130 ± 20	480 ± 60	150
Transcript 42	59U→G	160 ± 30	340 ± 60	80
Transcript 43	60U→G	ND	ND	<5a

^a The relative initial velocities were calculated from the time course experiment for 30 min. <5 and <10 mean that the relative initial velocity was below 5% and 10% of that for T. thermophilus tRNA^Phe, respectively.