Neuronal Tissue-Nonspecific Alkaline Phosphatase (TNAP)
Place of Publication
978-9401771962 / 9401771960
Two observations stimulated the interest in vitamin B-6 and alkaline phosphatase in brain:the marked increase in plasma pyridoxal phosphate and the occurrence of pyridoxine responsive seizures in hypophosphatasia.The increase in plasma pyridoxal phosphate indicates the importance of tissue non-specific alkaline phosphatase (TNAP) in transferring vitamin B-6 into the tissues.Vitamin B-6 is involved in the biosynthesis of most of the neurotransmitters.Decreased gamma-aminobutyrate (GABA) appears to be most directly related to the development of seizures in vitamin B-6 deficiency.Cytosolic pyridoxal phosphatase/chronophin may interact with vitamin B-6 metabolism and neuronal development and function.Ethanolaminephosphate phospholyase interacts with phosphoethanolamine metabolism.Extracellular pyridoxal phosphate may interact with purinoceptors and calcium channels.In conclusion, TNAP clearly influences extracellular and intracellular metabolism of vitamin B-6 in brain, particularly during developmental stages.While effects on GABA metabolism appear to be the major contributor to seizures, multiple other intra- and extra-cellular metabolic systems may be affected directly and/or indirectly by altered vitamin B-6 hydrolysis and uptake resulting from variations in alkaline phosphatase activity.
vitamin B-6, alkaline phosphatase, brain, hypophosphatasia
Biochemistry | Chemistry
Stephen P. Coburn (2015).
Vitamin B-6 Metabolism and Interactions with TNAP. Neuronal Tissue-Nonspecific Alkaline Phosphatase (TNAP). 207-238. London: Springer.