Table 3. Kinetic parameters of PcGSTFuAs and CcGSTFuAs in enzymatic assays.
| Km (μM) | PcGSTFuA1 | PcGSTFuA2 | PcGSTFuA3 | PcGSTFuA4 | CcGSTFuA2461 | CcGSTFuA6800 | CcGSTFuA6801 | CcGSTFuA6820 |
| CDNB | ND | ND | ND | ND | 4205±557 | ND | 1172±84.96 | ND |
| Tertbutyl | ND | ND | ND | ND | ND | ND | ND | ND |
| Cumen | ND | ND | 2037±556 | ND | ND | ND | ND | ND |
| H2O2 | ND | ND | ND | ND | ND | ND | ND | ND |
| HED | ND | ND | ND | ND | ND | ND | ND | ND |
| DHA | ND | ND | ND | ND | ND | ND | ND | ND |
| ITC | 119.0±14.4 | ND | 53.16±5.37 | ND | 191.2±17.8 | 2431±254 | 41.56±3.73 | ND |
| PNP-butyrate | 774.3±88.3 | ND | 612.6±81.1 | ND | ND | ND | 177.7±8.9 | ND |
| CMFDA (-GSH) | 3.6±0.6 | ND | ND | ND | ND | 0.153±0.023 | 0.945±0.074 | ND |
| CMFDA (+GSH) | 8.0±0.8 | 1.07±0.16 | 5.1±0.5 | 1.442±0.07 | ND | 5.05±1.29 | 3.13±0.73 | ND |
| GSH | 216.4±34.9 | ND | 21.1±3.6 | ND | 435.0±29.4 | 474.9±43.8 | 167.3±10.5 | ND |
| kcat (min−1) | PcGSTFuA1 | PcGSTFuA2 | PcGSTFuA3 | PcGSTFuA4 | CcGSTFuA2461 | CcGSTFuA6800 | CcGSTFuA6801 | CcGSTFuA6820 |
| CDNB | ND | ND | ND | ND | 443.2±39.6 | ND | 251.9±8.1 | ND |
| Tertbutyl | ND | ND | ND | ND | ND | ND | ND | ND |
| Cumen | ND | ND | 76.70±9.78 | ND | ND | ND | ND | ND |
| H2O2 | ND | ND | ND | ND | ND | ND | ND | ND |
| HED | ND | ND | ND | ND | ND | ND | ND | ND |
| DHA | ND | ND | ND | ND | ND | ND | ND | ND |
| ITC | 510.9±16.0 | ND | 130.9±2.9 | ND | 368.1±10.3 | 469.2±29.9 | 1065.0±20.2 | ND |
| PNP-butyrate | 165.0±5.6 | ND | 246.5±10.2 | ND | ND | ND | 115.7±1.4 | ND |
| CMFDA (-GSH) | 0.006±0.0002 | ND | ND | ND | ND | 0.123±0.003 | 0.343±0.005 | ND |
| CMFDA (+GSH) | 0.17±0.04 | 0.033±0.001 | 0.65±0.02 | 0.002±0.0001 | ND | 0.39±0.05 | 0.85±0.08 | ND |
| GSH | 662.0±14.2 | ND | 52.33±1.68 | ND | 46.01±2.45 | 37.15±1.6 | 31.95±0.53 | ND |
| kcat/Km (min−1/μM−1) | PcGSTFuA1 | PcGSTFuA2 | PcGSTFuA3 | PcGSTFuA4 | CcGSTFuA2461 | CcGSTFuA6800 | CcGSTFuA6801 | CcGSTFuA6820 |
| CDNB | ND | ND | ND | ND | 0.11±0.07 | ND | 0.21±0.09 | ND |
| Tertbutyl | ND | ND | ND | ND | ND | ND | ND | ND |
| Cumen | ND | ND | 0.037±0.017 | ND | ND | ND | ND | ND |
| H2O2 | ND | ND | ND | ND | ND | ND | ND | ND |
| HED | ND | ND | ND | ND | ND | ND | ND | ND |
| DHA | ND | ND | ND | ND | ND | ND | ND | ND |
| ITC | 4.3±0.3 | ND | 2.46±0.54 | ND | 1.92±0.58 | 0.19±0.11 | 25.62±5.41 | ND |
| PNP-butyrate | 0.21±0.01 | ND | 0.40±0.12 | ND | ND | ND | 0.65±0.16 | ND |
| CMFDA (-GSH) | 0.0017±0.0002 | ND | ND | ND | ND | 0.82±0.13 | 0.36±0.06 | ND |
| CMFDA (+GSH) | 0.021±0.002 | 0.031±0.006 | 0.13±0.04 | 1.39*10−3±0.14*10−3 | ND | 0.077±0.038 | 0.27±0.11 | ND |
| GSH | 3.1±0.4 | ND | 2.48±0.47 | ND | 0.11±0.08 | 0.078±0.036 | 0.19±0.05 | ND |
The apparent Km values for all compounds were determined using a concentration range of 0.1–10 mM in the presence of 5 mM GSH. The Km value for GSH was determined with 1 mM Phenethyl-ITC for PcGSTFuA1, PcGSTFuA3, CcGSTFuA2461, CcGSTFuA6801 and 50 µM CMFDA for CcGSTFuA6800 with a concentration range of 0.01 to 10 mM GSH. The apparent Km and kcat values were calculated by nonlinear regression using the Michaelis-Menten equation (r2>0.99). Data are represented as mean ± S.D. (n±3). ND: Not Detected. The detection limit was estimated at 0.5 mUI.