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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2010-6-29
pubmed:abstractText
We have examined the activity of the thiamin phosphate pyrophosphorylase in Arabidopsis thaliana wild type and in a mutant (th-1) which requires exogenous thiamin for growth. Mutant and wild-type plants grown in 1 x 10(-7) molar thiamin were used for the examination of the production of thiamin and thiamin monophosphate (TMP) using 4-methyl-5-hydroxyethylthiazole phosphate and 2-methyl-4-amino-5-hydroxymethylpyrimidine pyrophosphate as substrates. While the wild-type strain formed both thiamin and TMP, the th-1 mutant did not. When TMP was added to the extracts, the th-1 mutant, as well as wild type, produced thiamin. Accordingly, it was concluded that the th-1 mutant was defective in the activity of TMP pyrophosphorylase. Some of the characteristics of the enzyme from the wild-type plant were examined. The optimum temperature for the reaction is 45 degrees C, and the K(m) values for the substrates are 2.7 x 10(-6) molar for 4-methyl-5-hydroxyethylthiazole phosphate and 1.8 x 10(-6) molar for 2-methyl-4-amino-5-hydroxymethylpyrimidine pyrophosphate.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Oct
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
88
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
248-50
pubmed:dateRevised
2010-9-15
pubmed:year
1988
pubmed:articleTitle
A th-1 Mutant of Arabidopsis thaliana Is Defective for a Thiamin-Phosphate-Synthesizing Enzyme: Thiamin Phosphate Pyrophosphorylase.
pubmed:affiliation
Molecular Genetics Research Laboratory, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan.
pubmed:publicationType
Journal Article