. So far, no corresponding enzymes are
known for the specific catalysis of these two reactions. We then
explore enzyme promiscuity to fill the gaps in order to complete
the whole pathway. The deamination of serine can be catalyzed by
aminotransferase (E.C. 2.6.1-) or amino acid dehydrogenase (E.C.
1.4.1-). The decarboxylation of hydroxypyruvate can be catalyzed
by α-ketoacid decarboxylase (E.C. 4.1.1-).