## 2 Materials and Methods
### PON1 Activity  
Arylesterase (AREase) activity was measured using phenylacetate as a substrate [32]. The mix reaction consisted of 2.7 mL of buffer (10 mM Tris-HCl, 40 uM serine hemisulfate, 1 mM CaCl\({}_{2}\), pH 8.0) and 20 uL of plasma diluted at 1:50 and was incubated for 5 min in the dark at room temperature following the addition of 300 uL of phenylacetate (10 mM). The change in absorbance was monitored at 270 nm for 5 min at 37 \({}^{\circ}\)C in a Spectromic GENESYS(tm) 10 spectrophotometer from Bio-Thermo Scientific. AR-Ease activity was reported in U/mL according to the molar extinction coefficient of phenylacetate (\(\varepsilon=1.31\times 10^{3}\) M\({}^{-1}\) cm\({}^{-1}\)). One unit of AREase activity is equivalent to 1 umol of phenylacetate hydrolyzed/min/mL of plasma.  
CMPAase activity was measured through 4-chloromethylphenylacetate (4-CMPA) hydrolysis [33]. The mix reaction consisted of 295.2 uL of buffer (20 mM Tris-HCl, 1 mM CaCl\({}_{2}\), pH 8.0), 60 uL of plasma diluted (1:40) in buffer, and 304.8 uL of 4-CMPA (3 mM). Absorbance change was monitored at 280 nm for 5 min at 25 \({}^{\circ}\)C in a Spectromic GENESYS(tm) 10 spectrophotometer from Bio-Thermo Scientific. CMPAase activity was expressed in U/mL according to the molar extinction coefficient of 4-CMPA (\(\varepsilon=1.30\) mM\({}^{-1}\) cm\({}^{-1}\)). One unit of CMPAase activity is equal to 1 umol of 4-CMPA hydrolyzed/min/mL of plasma.  
Lactonase (LACase) activity was determined using dihydrocumarin (DHC) as substrate through the modified method as described by [PERSON] et al. [34]. The reaction mix was consisted of 987.5 uL of buffer (40 mM Tris-HCl, 1 mM CaCl\({}_{2}\), pH 8.0), 10 uL of 100 mM DHC and 2.5 uL of serum. The hydrolysis of DHC was monitored at 270 nm for 3 min at 25 \({}^{\circ}\)C using a Spectromic GENESYS(tm) 10 spectrophotometer from Bio-Thermo Scientific. LACase activity was expressed in U/mL according to the DHC molar extinction coefficient (\(\varepsilon=1295\) M\({}^{-1}\) cm\({}^{-1}\)). One unit of LACase activity is equal to 1 umol of DHC hydrolyzed/min/mL of serum.  
Paraoxonase (PONase) activity of salt-stimulated PONase was measured using ethylparaxon as a substrate [35]. The mix reaction contained 795 uL of buffer (10 mM Tris-HCl, 1 mM CaCl\({}_{2}\), 1 M NaCl, pH 8.0), 5 uL of plasma, and 200 uL of ethyl paraoxon (6 mM). The hydrolysis of ethyl paraoxon at 405 nm was monitored for 5 min at 37 \({}^{\circ}\)C using a Spectromic GENESYS(tm) 10 spectrophotometer from Bio-Thermo Scientific. One unit of PONase activity is equal to 1 umol of ethyl paraoxon hydrolyzed/min/L of plasma. The molar extinction coefficient of \(p\)-nitrophenol was used (\(\varepsilon=1.8\times 10^{3}\) M\({}^{-1}\) cm\({}^{-1}\)), and PONase activity was expressed as U/L.  
Internal controls with known activities were utilized in each set of samples. The reproducibility of the enzymatic analyses was assessed in the triplicate analyses of plasma samples. In each case, the coefficient of variation calculated was 5% or less.  
PON1 specific enzymatic activity represents the quotient of enzymatic activity through a specific substrate (AREase; CMPAase; LACase; PONase) and PON1 protein concentration.