Linked Life Data

1643284

Source:http://linkedlifedata.com/resource/pubmed/id/1643284

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1992-9-8
pubmed:abstractText
The essential amino acid lysine is synthesized in higher plants by a complex pathway that is predominantly regulated by feedback inhibition of two enzymes, namely aspartate kinase (AK) and dihydrodipicolinate synthase (DHPS). Although DHPS is thought to play a major role in this regulation, the relative importance of AK is not known. In order to study this regulation, we have expressed in the chloroplasts of transgenic potato plants a DHPS derived from Escherichia coli at a level 50-fold above the endogenous DHPS. The bacterial enzyme is much less sensitive to lysine inhibition than its potato counterpart. DHPS activity in leaves, roots and tubers of the transgenic plants was considerably higher and more resistant to lysine inhibition than in control untransformed plants. Furthermore, this activity was accompanied by a significant increase in level of free lysine in all three tissues. Yet, the extent of lysine overproduction in potato leaves was significantly lower than that previously reported in leaves of transgenic plants expressing the same bacterial enzyme, suggesting that in potato, AK may also play a major regulatory role in lysine biosynthesis. Indeed, the elevated level of free lysine in the transgenic potato plants was shown to inhibit the lysine-sensitive AK activity in vivo. Our results support previous reports showing that DHPS is the major rate-limiting enzyme for lysine synthesis in higher plants, but they suggest that additional plant-specific regulatory factors are also involved.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0167-4412
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:geneSymbol
DHPS, dapA
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
815-23
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Regulation of lysine synthesis in transgenic potato plants expressing a bacterial dihydrodipicolinate synthase in their chloroplasts.
pubmed:affiliation
Department of Plant Genetics, Weizmann Institute of Science, Rehovot, Israel.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't