Table 2. Enzymatic characterisation of OPHC2 enzyme.
Substrates | kcat (s−1) | KM (µM) | kcat/KM (M−1s−1) | |
Phosphoesters | Ethyl-paraoxon (I) | 4.05(±0.01)×10−3 | 94±19 | 1.33(±0.92)×101 |
Methyl-paraoxon (II) | 3.87(±0.29)×10−1 | 261±56 | 1.48(±0.34)×103 | |
Ethyl-parathion (III) | ND | ND | ND | |
Methyl-parathion (IV) | 5.71(±0.33)×10−2 | 21±6 | 2.68(±0.73)×103 | |
Malathion (V) | ND | ND | VLH | |
CMP-coumarin (VI) | 3.38(±0.19)×10−1 | 114±17 | 2.96(±0.48)×103 | |
Esters | Phenyl-acetate (VII) | 9.03(±1.26)×10−2 | 1620±563 | 5.56(±2.08)×101 |
p NP-Acetate (VIII) | ND | ND | 2.17(±0.08)×101 | |
p NP-Decanoate (IX) | 3.22(±0.25)×10−2 | 138±48 | 2.33(±0.83)×102 | |
Lactones | AHLs (X–XV) | ND | ND | ND |
oxo-lactones (XVI–XX) | ND | ND | ND | |
Di-hydrocoumarin (XXI) | 2.39±0.20 | 403±100 | 5.93(±1.55)×103 |
Roman numbers correspond to the related chemical structure of the substrate presented in Figure S1. Data obtained with cobalt as cofactor. ND corresponds to not determined values because of no or too low catalytic rate. VLH correspond to Very Low Hydrolysis observed without the possibility to record a value.