Table 2.
Mechanismb | 1 | 2 | 3 | 4 |
---|---|---|---|---|
Constantc | α = 0 | α = β = 0 | β = 0 | |
KmB | 0.219 ± 0.073** | 0.199 ± 0.174† | 0.219 ± 0.120† | 0.199 ± 0.279† |
KmA | 1.02 ± 0.29** | 1.51 ± 1.03† | 1.02 ± 0.46* | 1.51 ± 1.53† |
Ksi(B→E) | 1.93 ± 0.28*** | - | 1.93 ± 0.37*** | - |
1.03 ± 0.34** | 0.550 ± 0.403† | 1.03 ± 0.50† | 0.550 ± 0.560† | |
KiB | - | - | ~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 |
a Least-squares non-linear regression was performed by using KyPlot [45].
b Mechanisms 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.
c K 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.