Regarding 4-pyridoxic acid-5′-phosphate in animal tissue

Wei, Kwo-Tsair H.; Bell, Roma R.; Haskell, Betty E.

doi:10.1016/0006-291x(72)90907-2

Cited by 6 publications

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In aerobic conditions, the principal breakdown (oxidation) products include 4-pyridoxic acid-5 0 -phosphate and the dipyridyl a-diketone. In anaerobic conditions, the acyloin is produced (Morrison and Long 1958;Wei et al 1972;Bazhulina et al 1974).…”

Section: Discussionmentioning

confidence: 99%

Cirrhosis Associated with Pyridoxal 5′-Phosphate Treatment of Pyridoxamine 5′-Phosphate Oxidase Deficiency

et al. 2014

View full text Add to dashboard Cite

We report the case of an 8-year-old boy with pyridoxamine 5 0 -phosphate oxidase (PNPO) deficiency. He developed seizures at 24 h of age that were refractory to standard anticonvulsant therapy and a trial of pyridoxine but responded to pyridoxal phosphate (PLP) at 28 days of life. Genetic testing identified compound heterozygous mutations in the PNPO gene. Management of encephalopathic episodes required escalation of PLP dose to 100 mg/kg/day by 2 years of age. Routine blood tests at this time showed significantly deranged liver function tests (LFTs). A wedge liver biopsy showed early cirrhosis with marked elevation of pyridoxal and pyridoxic acid levels in the liver sample. Despite extensive investigation, no cause other than PLP therapy could be identified for the cirrhosis. The PLP dose was weaned to 50 mg/kg/day before episodes of encephalopathy recurred. Concurrent with the reduction of his PLP dose, LFTs showed improvement. However, at 8 years of age, there is persistent evidence of hepatic fibrosis and early portal hypertension. We hypothesise that hepatic toxicity due to PLP or its degradation products is the cause of cirrhosis in this boy. Until further evidence becomes available, we would suggest that people with PNPO deficiency are treated with the minimum dose of PLP required to prevent episodes of encephalopathy.

show abstract

Section: Discussionmentioning

confidence: 99%

Cirrhosis Associated with Pyridoxal 5′-Phosphate Treatment of Pyridoxamine 5′-Phosphate Oxidase Deficiency

et al. 2014

View full text Add to dashboard Cite

show abstract

“…4-Pyridoxic acid is the only inactive derivative of vitamin B6 group identified so far [16]. Some authors claimed that 4-pyridoxic acid-5-phosphate is also an inactive excretory form, but it was shown that 4-pyridoxic acid-5-phosphate is an artefact, produced by the influence of light [20].…”

Section: Discussionmentioning

confidence: 99%

New Pathway of Conversion of Pyridoxal to 4-Pyridoxic Acid

Stanulović

Jeremić

Leskovac

et al. 1976

Enzyme

View full text Add to dashboard Cite

The only enzyme demonstrated so far to catalyze the formation of 4-pyridoxic acid, the final excretory product of vitamin B(6), was aldehyde oxidase. In this paper we have presented an evidence that another enzyme, NAD^+-dependent aldehyde dehydrogenase, is capable of catalyzing this reaction. Rat mutants with high, low and no aldehyde oxidase activity excrete the same amount of isotope after a single injection of ³H-pyridoxol in a 12-day experiment; 4-pyridoxic acid is also present in the urine of animals without aldehyde oxidase activity. There is no correlation between the proportion of the excreted acid and the amount of pyridoxal excreted, after the injection of a single dose of the aldehyde form. The K(m) values for pyridoxal and NAD^+, at pH 9.6, have been found to be 75 and 260 μmol/1, respectively. NAD^+-dependent pyridoxal dehydrogenase was partially purified from the rat tissues, and the following specific enzyme activities (nmol·min^-1·mg^-1 protein) were found: red blood cell 71.5±3.0, intestine 64.9 ±9.0, muscle 61.4 ±1.6, brain 39.5 ±6.0, liver 34.4 ±3.3, kidney 21.1 ±5.6, heart 18.8±0.9, and lung 6.5±2.0. This is believed to be the first report demonstrating pyridoxal oxidation, catalyzed by an NAD^+-dependent aldehyde dehydrogenase.

show abstract

Pyridoxamine (pyridoxine) phosphate oxidase activity in mammalian tissues

Fonda

1988

Comparative Biochemistry and Physiology Part B: Comparative Bio

View full text Add to dashboard Cite

Regarding 4-pyridoxic acid-5′-phosphate in animal tissue

Cited by 6 publications

References 8 publications

Cirrhosis Associated with Pyridoxal 5′-Phosphate Treatment of Pyridoxamine 5′-Phosphate Oxidase Deficiency

Cirrhosis Associated with Pyridoxal 5′-Phosphate Treatment of Pyridoxamine 5′-Phosphate Oxidase Deficiency

New Pathway of Conversion of Pyridoxal to 4-Pyridoxic Acid

Pyridoxamine (pyridoxine) phosphate oxidase activity in mammalian tissues

Contact Info

Product

Resources

About