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Entry URI http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u17172352i
Entry name Joshi Vijay et al. 2006 Dec. Plant Cell 18(12):3564-75.
Title Two Arabidopsis threonine aldolases are nonredundant and compete with threonine deaminase for a common substrate pool.
Authors Fernie Alisdair R|Jander Georg|Joshi Vijay|Laubengayer Karen M|Schauer Nicolas
Abstract Amino acids are not only fundamental protein constituents but also serve as precursors for many essential plant metabolites. Although amino acid biosynthetic pathways in plants have been identified, pathway regulation, catabolism, and downstream metabolite partitioning remain relatively uninvestigated. Conversion of Thr to Gly and acetaldehyde by Thr aldolase (EC 4.1.2.5) was only recently shown to play a role in plant amino acid metabolism. Whereas one Arabidopsis thaliana Thr aldolase (THA1) is expressed primarily in seeds and seedlings, the other (THA2) is expressed in vascular tissue throughout the plant. Metabolite profiling of tha1 mutants identified a >50-fold increase in the seed Thr content, a 50% decrease in seedling Gly content, and few other significant metabolic changes. By contrast, homozygous tha2 mutations cause a lethal albino phenotype. Rescue of tha2 mutants and tha1 tha2 double mutants by overproduction of feedback-insensitive Thr deaminase (OMR1) shows that Gly formation by THA1 and THA2 is not essential in Arabidopsis. Seed-specific expression of feedback-insensitive Thr deaminase in both tha1 and tha2 Thr aldolase mutants greatly increases seed Ile content, suggesting that these two Thr catabolic enzymes compete for a common substrate pool.
Pubmed ID 17172352
Journal The Plant cell
Volume 18
Issue 12
Pages 3564-75
Publication date 2006 Dec
Num of phenotype gene 2