Biochemical properties
Our literature searches identified a total of 34 enzymes that have been
shown to catalyse the partial degradation of PET to oligomers or even to
monomers, originating from four different bacterial phyla and one
eukaryotic lineage (Table 1 ). No archaeal PETases have been
functionally verified to date.
Many of the currently known PETases are thermostable enzymes, because
the catalytic activity increases at temperatures close to the glass
transition temperature (65 °C) of PET due to the formation of flexible
and thus enzyme-accessible amorphous domains 28.
Notably, few enzymes are active at lower temperatures implying they may
play a role in cold-adapted PET degradation 29.
However, all known native PETases have rather low catalytic activity
toward PET.