Families of PLP-dependent proteins are defined as monophyletic groups of sequences possessing the same enzymatic function.

1. metser_aldolase alpha-methylserine aldolase (4.1.2.-)
2. odcp Ornithine decarboxylase paralogue
3. cold GDP-4-keto-6-deoxy-D-mannose-3-dehydratase (4.3.1.-)
4. beta_transaminase Beta-amino acid--oxoglutarate aminotransferase (2.6.1.-)
5. sec_synthase L-phosphoseryl-tRNA(Ser):selenophosphate seleniumtransferase (2.9.1.-)