Table 1 Kinetic parameters of MHETase.

The kinetic parameters were determined in pH 7.0 buffer at 30°C. Because the enzymatic PET hydrolysis involves a heterogeneous reaction, Michaelis–Menten kinetics were not applied to PETase. ND, not detected (activity was below the detection limit of the assay).

Substratekcat (s−1)Km (μM)
MHET31 ± 0.8*7.3 ± 0.6*
PET filmND
BHET0.10 ± 0.004†
pNP-aliphatic esters (pNP-acetate, pNP-butyrate)ND
Aromatic esters (ethyl gallate, ethyl ferulate, chlorogenic acid hydrate)ND

*Data are shown as means ± SEs based on a nonlinear regression model.   †The reported kcat is the apparent kcat determined with 0.9 mM BHET. Shown is the mean ± SE from three independent experiments.