FIG 1.

Previously reported mechanisms of β-alanine biosynthesis in bacteria and eukaryotes. (A) Direct decarboxylation of Asp by aspartate decarboxylase (ADC) utilized in bacteria and insects. (B) Conversion from uracil via three enzymatic reactions catalyzed by dihydropyrimidine dehydrogenase (PYD1), dihydropyrimidinase (PYD2), and β-ureidopropionase (PYD3) utilized in plants. (C) Oxidation of spermine by polyamine oxidase (FMS1) and aldehyde dehydrogenases (ALD2 and ALD3) utilized in Saccharomyces cerevisiae.