Table 2.

Steady state kinetics data for transacetylation by wild type and Y190 mutants at 25°C and pH 7.0

	Hamster NAT2	Ka (mM)	Kb (mM)	kcat (s⁻¹)	kcat/Ka (s⁻¹mM⁻¹)	kcat/Kb (s⁻¹mM⁻¹)
PNPA/Anisidine	WT^a	2.8 ± 0.4^a	0.34 ± 0.04^a	260 ± 20^a	100 ± 20^a	790 ± 120^a
	Y190F	7.8 ± 0.6	0.58 ± 0.04	288 ± 14	37 ± 4	496 ± 58
	Y190I	10.1 ± 1.5	0.18 ± 0.03	85 ± 12	8.4 ± 2.4	483 ± 160
	Y190A	7.4 ± 0.5	0.25 ± 0.02	28 ± 2	3.8 ± 0.6	114 ± 16

PNPA/PABA	WT^a	10 ± 1^a	0.23 ± 0.02^a	620 ± 40 ^a	62 ± 9 ^a	2700 ± 400^a
	Y190F	7.7 ± 0.9	0.22 ± 0.01	393 ± 29	51 ± 10	1786 ± 214
	Y190I	4.5 ± 0.7	0.08 ± 0.01	60 ± 4	13 ± 3	746 ± 146
	Y190A	7.5 ± 0.5	0.11 ± 0.01	38 ± 2	5 ± 1	345 ± 46

PNPA/pABglu	WT^a	1.5 ± 0.1^a	1.7 ± 0.1^a	120 ± 3^a	86 ± 3^a	70 ± 5^a
	Y190F	2.8 ± 0.2	2.5 ± 0.2	86 ± 3	30 ± 3	34 ± 4
	Y190I	11 ± 1	2.7 ± 0.2	77 ± 4	7 ± 1	28 ± 4
	Y190A	5.6 ± 0.6	6.2 ± 0.6	16 ± 1	2.8 ± 0.5	2.6 ± 0.4

AcCoA/PNA	WT^a	0.037 ± 0.003^a	0.77 ± 0.06^a	0.60 ± 0.02^a	16 ± 2^a	0.78 ± 0.08^a
	Y190F	0.14 ± 0.03	0.48 ± 0.10	0.31 ± 0.03	2.23 ± 0.79	0.66 ± 0.21
	Y190I	0.71 ± 0.18	1.51 ± 0.44	0.89 ± 0.15	1.26 ± 0.54	0.60 ± 0.27
	Y190A	1.49 ± 0.8	2.92 ± 1.64	0.25 ± 0.11	0.17 ± 0.16	0.087 ± 0.086

AcCoA/PABA	WT^a	3.4 ± 0.3^a	0.12± 0.01^a	200 ± 1^a	60 ± 6^a	1700 ± 200^a
	Y190F	1.8 ± 0.2	0.14 ± 0.02	189 ± 17	106 ± 15	1360 ± 226
	Y190I	1.9 ± 0.6	0.06 ± 0.01	58 ± 9	30 ± 13	974 ± 377
	Y190A	2.7 ± 0.9	0.28 ± 0.10	8.14± 2.23	3± 1	29 ± 11

Values for the “wild type” protein are taken from previously published research articles: [27]