Table III.

Table of characteristics for directed evolution

Round	Variant	Acquired mutation	Codon change	kcat (s−1)		KM (µM)		kcat/KM (M−1 s−1)
				Inosine	ddI	Inosine	ddI	Inosine (×102)	ddI
	Wild type	–	–	43.9 ± 0.6	0.90 ± 0.01	48 ± 2	1030 ± 20	9210 ± 140	875 ± 8
Rational	Y88F	Y88F	TAT→TTT	28.3 ± 0.8	10.5 ± 0.1	73 ± 4	450 ± 10	3890 ± 110	23 140 ± 230
DE-1	19E2	M170T	ATG→ACG	9.6 ± 0.2	5.8 ± 0.1	26 ± 1	230 ± 15	3710 ± 70	25 160 ± 620
DE-2	30F2	G4E	GGA→GAA	14.5 ± 0.3	6.1 ± 0.1	37 ± 2	247 ± 10	3970 ± 90	24 650 ± 330
		Q172L	CAG→CTG
		C206C	TGT→TGC
DE-3	46D6	T177A	ACC→GCC	14.7 ± 0.7	4.5 ± 0.1	33 ± 4	235 ± 11	4390 ± 280	19 240 ± 320