The classical studies of Rabinowitz and Snell (1) demonstrated that vitamin Be exists in at least three forms in the tissues of animals and plants: pyridoxine, pyridoxamine, and pyridoxal. Their assay procedure, a differential growth response of microorganisms to pyridoxine, pyridoxamine, and pyridoxal, would not differentiate between the phosphorylated and the nonphosphorylated forms of the vi...

Alkaline phosphatase (ALP) activity was detected using bovine serum albumin (BSA)-functionalized manganese-doped zinc sulfide (Mn–ZnS) quantum dots (QDs), and the phosphate substrate vitamin-B 6 cofactor pyridoxal 5′-phosphate (PLP).

1. The effect of pyridoxal 5'-phosphate on the activity of ox liver glutamate dehydrogenase towards different amino acid substrates was investigated. 2. Both alanine and glutamate activities decreased steadily in the presence of pyridoxal 5'phosphate. 3. The alanine/glutamate activity ratio increased as a function of inactivation by pyridoxal 5'-phosphate, indicating that glutamate activity is ...

Tritium-labeled pyridoxamine, pyridoxal S/-phosphate, and pyridoxine 5’-phosphate were prepared and administered intravenously to mice, and the distribution of isotope in liver and carcass between pyridoxine, pyridoxine 5’-phosphate, pyridoxal, pyridoxal S/-phosphate, pyridoxamine, and pyridoxamine 5’-phosphate was determined at different times after administration. The vitamin B6 forms were ex...

Dempsey, Walter B. (University of Florida, Gainesville). Synthesis of pyridoxine by a pyridoxal auxotroph of Escherichia coli. J. Bacteriol. 92:333-337. 1966.-A pyridoxal auxotroph of Escherichia coli B produced pyridoxol and pyridoxol 5'-phosphate during starvation for pyridoxal. The identification of these compounds was made both by bioassay and by ion-exchange chromatography. Pyridoxol 5'-ph...

Pyridoxal 5•L-phosphate (PLP) is known to combine with bovine serum albumin to form a(1:1) complex which scarcely dissociates, even when subjected to intensive dialysis. When this complex was incubated with apo-aspartate aminotransferase (apoGOT) for an appropriate time and the preincubated mixture then submitted to the usual GOT assay, the appearance of GOT activity was obviously confirmed, in...

To investigate the role of the essential cofactor pyridoxal phosphate in rabbit muscle glycogen phosphorylase catalysis, two phosphonate analogues of pyridoxal phosphate, 5'-deoxypyridoxal 5'-methylenephosphonic acid and 5'-deoxypyridoxal 5'-difluoromethylenephosphonic acid, have been prepared and reconstituted into apophosphorylase b. UV/Vis spectroscopic and 31P and 19F NMR studies confirmed ...

1. Pig heart mitochondrial malate dehydrogenase incubated with pyridoxal 5'-phosphate at pH 8.0 and 25 degrees C gradually loses activity. Such inactivation can be largely reversed by dialysis or by addition of L-lysine or L-cysteine, and can be made permanent by NaBH4 reduction. 2. Modification of malate dehydrogenase with pyridoxal 5'-phosphate at 35 degrees C involves two phases, an initial ...