TABLE 1.

Sulfonate specificity and kinetic parameters for sulfonate/α-KG dioxygenase

Substratea	Vmax (μmol/min/mg)	Km (mM)	kcat/Km (min−1/mM)	Ki (mM)
3-N-Morpholinopropanesulfonic acid (MOPS) (0–20 mM)	1.80 ± 0.06	0.24 ± 0.02	670.9	34.3 ± 5.8b
N-Phenyltaurine (0–3 mM)	0.81 ± 0.03	0.12 ± 0.01	606.4	1.5 ± 0.1b
2-Hydroxyethanesulfonate (isethionate) (0–20 mM)	1.26 ± 0.05	0.27 ± 0.05	418.4	20.3 ± 2.5b
3-Morpholino-2-hydroxypropanesulfonic acid (MOPSO) (0–20 mM)	1.51 ± 0.03	0.33 ± 0.02	411.2	28.4 ± 2.4b
Taurocholate (0–10 mM)	0.99 ± 0.05	0.42 ± 0.05	210.7	8.2 ± 1.1b
2-(4-Morpholino)ethanesulfonic acid (MES) (0–20 mM)	1.48 ± 0.05	1.94 ± 0.14	68.4	45.2 ± 6.6b
2-(Cyclohexylamino)ethanesulfonic acid (CHES) (0–20 mM)	0.56 ± 0.02	2.57 ± 0.34	19.6	—c
N-(Tris[hydroxymethyl]methyl)-2-amino-ethanesulfonic acid (TES) (0–15 mM)	0.75 ± 0.01	3.60 ± 0.12	18.7	—c
N-[2-Hydroxyethyl] piperazine-N′-[2-hydroxy-propanesulfonic acid] (HEPPSO) (0–20 mM)	1.01 ± 0.08	5.04 ± 1.07	18.0	—c
N-(Tris(hydroxymethyl)methyl)-3-aminopropane sulfonic acid (TAPS) (0–20 mM)	1.61 ± 0.06	10.38 ± .80	13.9	—c
4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (0–20 mM)	0.82 ± 0.02	16.62 ± 0.80	4.4	—c
2-Aminoethanesulfonic acid (taurine) (0–20 mM)	0.46 ± 0.04	10.37 ± 1.82	4.0	—c

^aThe concentrations of substrates examined are shown in parentheses. 

^bData for these substrates were fit to the equation given in the text. 

^cNo inhibition was detected. Kinetic parameters were fit to the Michaelis-Menten equation.