Kinetic characterisation of arylamine N-acetyltransferase from Pseudomonas aeruginosa

BMC Biochemistry

Table 2 Results of non-linear regression by the least-squares method.^a

Mechanism^b	1	2	3	4
Constant^c	α = 0	α = β = 0		β = 0
K _mB	0.219 ± 0.073**	0.199 ± 0.174^†	0.219 ± 0.120^†	0.199 ± 0.279^†
K _mA	1.02 ± 0.29**	1.51 ± 1.03^†	1.02 ± 0.46*	1.51 ± 1.53^†
K _si(B→E)	1.93 ± 0.28***	-	1.93 ± 0.37***	-
$K_{si (B \to_{FP}^{EA})}$	1.03 ± 0.34**	0.550 ± 0.403^†	1.03 ± 0.50^†	0.550 ± 0.560^†
K _iB	-	-	~0.00 ± 0.01^†	~0.00 ± 0.01^†
den	0.422 ± 0.105***	0.512 ± 0.327^†	0.422 ± 0.156*	0.512 ± 0.463^†
den _(calc)	0.408	0.491	0.408	0.491
Sum of squares	0.268	1.254	0.268	1.254
Bi Bi Mechanism	Ping Pong	Ping Pong	Ordered	Ordered
Substrate inhibition by 5-aminosalicylic acid on free enzyme?	Yes	No	Yes	No

^aLeast-squares non-linear regression was performed by using KyPlot [45].
^bMechanisms 1 and 2 refer to Ping Pong Bi Bi kinetics allowing 5-aminosalicylic acid to act as an inhibitor of the enzyme·AcCoA complex (EA). Mechanism 1 also accounts for 5-aminosalicylic acid binding to the free enzyme (E). Mechanisms 3 and 4 are directly analogous to 1 and 2 respectively, however they refer to Ordered Bi Bi kinetics.
^cK values have dimensions of mM and den values are expressed in mM². α and β are defined in Table 1. Variance and statistical significance values were determined within KyPlot by Student's t test. ^†, P >= 0.05; *, P < 0.05; **, P < 0.01; ***, P < 0.001.

ISSN: 1471-2091