(1) B6 vitamers are first oxidized to pyridoxal , and rapidly phosphorylated to P5P in the liver.(2) This conversion is catalyzed by the ATP requiring enzyme, pyridoxal kinase.(3) The deuteration effects arose from the reversible deprotonation of the Schiff base formed between glutamate and pyridoxal phosphate.(4) The central domain is typical of class 1 pyridoxal - 5'-phosphate-dependent enzymes.
