Solubilization and Humanization of Paraoxonase-1

Table 1

Aryl esterase and OPase activity of huPON1 variants. Phenyl acetate and paraoxon specific activities were determined at 3.3 mM and 2.6 mM substrate, respectively. Errors for the specific activities are the standard errors from 3 trials. EMP values were determined at constant 2% methanol, and the errors are with respect to the fit. n.d.: not detected. —: k_cat/K_m is reported from a linear fit of initial rate versus substrate concentration when the enzyme could not be saturated under experimental conditions.

Variant	Phenyl acetate	Paraoxon		EMP
	specific activity μmol min^−1 mg^−1	specific activity μmol min^−1 mg^−1	kcat s^−1	Km mM	kcat/Km; M^−1 s^−1
huPON1	160±20	0.003±0.001	0.027±0.001	0.14±0.01	190±20
ΔN-	17±9	n.d.	—	—	117±8
g2e6p-	20±5	0.011±0.002	0.041±0.003	0.14±0.02	300±50
ΔN-g2e6p-	4±1	n.d.	—	—	2.2±0.1
ΔHDL-	1.2±0.2	n.d.		n.d.
ΔN-ΔHDL-	0.8±0.2	n.d.		n.d.