Linked Life Data

12492478

Source:http://linkedlifedata.com/resource/pubmed/id/12492478

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-12-20
pubmed:abstractText
Tocopherols are essential micronutrients in human and animal nutrition due to their function as lipophilic antioxidants. They are exclusively synthesized by photosynthetic organisms including higher plants. Despite the attributed beneficial health effects and many industrial applications, research on the tocopherol biosynthetic pathway and its regulation in plants is still limited. In the work presented here we performed a detailed biochemical characterization of a gamma-tocopherol methyltransferase (gamma-TMT) from Arabidopsis thaliana and of a gamma-TMT purified from Capsicum annuum fruits, a tissue with high accumulation of tocopherols. The biochemical characteristics of both enzyme preparations were remarkably similar including substrate specificities. Both enzymes converted delta- and gamma- into beta- and alpha-tocopherol, respectively, but beta-tocopherol was not accepted as a substrate, pointing to a specific methylation at the C(5)-position of the tocopherol aromatic head group. A kinetic analysis performed with the Arabidopsis enzyme was consistent with an iso-ordered bi-bi type reaction mechanism. Our results emphasize the role of gamma-TMT in regulating the spectrum of accumulated tocopherols in plants.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
84-92
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Characterization of gamma-tocopherol methyltransferases from Capsicum annuum L and Arabidopsis thaliana.
pubmed:affiliation
Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't