Rivero, M.; Novo, N.; Medina, M. Pyridoxal 5′-Phosphate BiosynthesisBy Pyridox-(am)-ine 5′-Phosphate Oxidase: Species-Specific Features. Int. J. Mol. Sci.2024, 25, 3174.
Rivero, M.; Novo, N.; Medina, M. Pyridoxal 5′-Phosphate BiosynthesisBy Pyridox-(am)-ine 5′-Phosphate Oxidase: Species-Specific Features. Int. J. Mol. Sci. 2024, 25, 3174.
Rivero, M.; Novo, N.; Medina, M. Pyridoxal 5′-Phosphate BiosynthesisBy Pyridox-(am)-ine 5′-Phosphate Oxidase: Species-Specific Features. Int. J. Mol. Sci.2024, 25, 3174.
Rivero, M.; Novo, N.; Medina, M. Pyridoxal 5′-Phosphate BiosynthesisBy Pyridox-(am)-ine 5′-Phosphate Oxidase: Species-Specific Features. Int. J. Mol. Sci. 2024, 25, 3174.
Abstract
Enzymes reliant on pyridoxal 5'-phosphate (PLP), the metabolically active form of vitamin B6, hold significant importance in both biology and medicine. They facilitate various biochemical reactions, particularly in amino acid and neurotransmitter metabolisms. Vitamin B6 is absorbed by organisms in its non-phosphorylated form and phosphorylated within cells by pyridoxal kinase (PLK) and pyridox-(am)-ine 5'-phosphate oxidase (PNPOx). The flavin mononucleotide dependent PNPOx enzyme converts pyridoxine 5'-phosphate and pyridoxamine 5'-phosphate into PLP. PNPOx is vital for both biosynthesis and salvage pathways in organisms producing B6 vitamers. However, for those depending on vitamin B6 as nutrient, PNPOx participates only in the salvage pathway. Transferring PLP produced by PNPOx to client apo-enzymes is indispensable for their catalytic function, proper folding and targeting to specific organelles. PNPOx activity deficiencies due to inborn errors lead to severe neurological pathologies, particularly neonatal epileptic encephalopathy. PNPOx enzymes from different organisms maintain PLP homeostasis through highly regulated mechanisms, including structural alterations throughout the catalytic cycle and allosteric PLP binding influencing substrate transformation at the active site. Despite shared features, species-specific regulations are evident among PNPOx enzymes.
Biology and Life Sciences, Biochemistry and Molecular Biology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
