TABLE 4.

Enzymatic activities of KatG mutants detected in this study

Plasmid	Amino acid mutation(s)		Mean activity ± SDa			Additional mutation associated with INH resistance	INH resistance levelb
	Not previously reported	Previously reported	INH oxidase (103A560 units)	Peroxidase (102A405 units)	Catalase (102A240 units)
pTrcHis2-TOPOc			4.84 ± 0.17	6.89 ± 0.70	0.00 ± 0.24
pkatG-wt			177.16 ± 18.50	286.08 ± 0.43	142.26 ± 0.16		S
pkatG-1		R463L	162.00 ± 11.31	289.62 ± 1.40	141.85 ± 0.13		S
pkatG-2	Q127E	R463L	60.18 ± 0.95	256.07 ± 7.80	143.21 ± 0.35	PfabG1-inhAC−15T	0.2
pkatG-3	P232S	R463L	54.47 ± 0.36	62.25 ± 0.05	76.63 ± 0.52		0.2
pkatG-4	N133T		40.67 ± 6.31	36.00 ± 0.26	100.61 ± 5.55		0.2
pkatG-5	S383P	R463L	38.49 ± 0.04	42.24 ± 3.64	107.65 ± 4.13	PfabG1-inhAC−15T	0.2
pkatG-6	KQT433-435QADd	R463L	20.02 ± 0.48	106.47 ± 1.17	142.81 ± 0.11	PfabG1-inhAC−15T	0.2
pkatG-7		H97R, R463L	17.42 ± 0.35	26.80 ± 0.44	27.86 ± 2.01		0.2
pkatG-8	R489S	R463L	10.40 ± 0.16	27.34 ± 0.27	14.83 ± 0.93	PfabG1-inhAC−15T	0.2
pkatG-9		S315T	8.83 ± 0.04	102.00 ± 2.54	71.26 ± 1.71		1.0
pkatG-10	M420T	R463L	8.42 ± 0.14	21.02 ± 0.37	46.45 ± 0.20		1.0
pkatG-11	D387H	S315T	7.93 ± 0.08	34.75 ± 0.61	35.71 ± 0.41		1.0
pkatG-12	G123E	G299S, R463L	6.87 ± 0.66	6.02 ± 0.17	−0.70 ± 1.42	PfabG1-inhAT−8C	1.0
pkatG-13		D419H, R463L	6.30 ± 0.52	7.67 ± 0.01	4.49 ± 0.39		1.0
pkatG-14	M176Te	R463L	5.14 ± 0.01	4.67 ± 0.07	1.06 ± 0.30	PfabG1-inhAC−15T	1.0
pkatG-15	Frame shiftf		5.02 ± 0.24	4.01 ± 0.57	−1.75 ± 1.16		1.0
pkatG-16		S315T, R463L	3.83 ± 0.18	84.41 ± 0.17	117.07 ± 7.56		1.0
pkatG-17	Frame shiftg		3.30 ± 0.69	4.59 ± 0.09	2.07 ± 1.51		1.0
pkatG-18	R632C	R463L	3.26 ± 0.13	1.56 ± 0.08	−7.41 ± 0.76		1.0
pkatG-19		S315R	3.19 ± 0.76	3.24 ± 0.02	−2.36 ± 0.71		1.0
pkatG-20	Δ(191W-192E)h	R463L	2.78 ± 0.09	2.09 ± 0.04	2.61 ± 1.86		1.0
pkatG-21	D542H	R463L	1.63 ± 0.49	0.32 ± 0.17	−7.00 ± 0.69		1.0

^aMean (n = 3) ± SD.

^bThe INH susceptibility levels for clinical isolates with katG mutations are shown, as follows: S, INH sensitive; 0.2, resistant to INH (0.2 μg/ml) and susceptible to INH (1.0 μg/ml); and 1.0, resistant to INH (1.0 μg/ml).

^cA vector control.

^d1297::C and Δ1305C.

^eThis isolate had an additional A65A silent mutation.

^fΔ(478-479).

^gΔ371G.

^hΔ(571-576).