Regarding the catalytic activity, we confirmed that the best substrate was 3OC12-HSL (Tables 1–3), in full agreement with the in vitro evidence of inhibition of PAO1 biofilm formation; the recombinant PON2 behaved better the other human paraoxonase PON1 (Fig 3), indicating that its physiological role could be the attenuation of infection of some pathogens by 3OC12-HSL hydrolysis, as previously hypothesized [17]. Here, PON2 is linked to infection.