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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1976-9-25
pubmed:abstractText
The only enzyme demonstrated so far to catalyze the formation of 4-pyridoxic acid, the final excretory product of vitamin B6, 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 Km values for pyridoxal and NAD+, at pH 9.6, have been found to be 75 and 260 mumol/l, 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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0013-9432
pubmed:author
pubmed:issnType
Print
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
357-69
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
New pathway of conversion of pyridoxal to 4-pyridoxic acid.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.