MetaCyc Enzyme: tryptophan synthase, beta subunit

Gene: TSB1 Accession Number: AT5G54810 (MetaCyc)

Species: Arabidopsis thaliana col

The Arabidopsis tryptophan synthase, like all other characterized tryptophan synthases, is composed of an alpha and a beta subunit. The alpha subunit catalyzes the conversion of indole-3-glycerolphosphate to indole, and the beta subunit, encoded by this and several other genes in Arabidopsis, catalyzes the formation of tryptophan from indole and serine [Last91]. There are two separate classes of tryptophan synthase beta proteins. This enzyme, TSB1, belongs to "type 1." Meanwhile, TSBType2 from Arabidopsis is a functional "type 2" tryptophan synthase beta protein [Yin10].

At least one functional gene encoding the alpha subunit, TSA1, has been cloned by functional complementation of an Escherichia coli mutant[Radwanski95]. On the other hand, there are two closely related genes encoding the beta subunit, TSB1 and TSB2. TSB1 is the predominantly expressed, whose mRNA accounts for 90% of the TSB transcripts[Last91]. A TSB1 mutant was shown lost about 90% of tryptophan synthase beta subunit activity.

Locations: plastid

Map Position: [22,281,820 -> 22,284,011]

Unification Links: PhylomeDB:P14671 , Phytozome Plant Orthologs:AT5G54810.1 , Pride:P14671 , Protein Model Portal:P14671 , SMR:P14671 , String:3702.AT5G54810.1-P , TAIR:AT5G54810 , UniProt:P14671

Relationship Links: InterPro:IN-FAMILY:IPR001926 , InterPro:IN-FAMILY:IPR006653 , InterPro:IN-FAMILY:IPR006654 , InterPro:IN-FAMILY:IPR023026 , Panther:IN-FAMILY:PTHR10314:SF3 , Pfam:IN-FAMILY:PF00291 , Prosite:IN-FAMILY:PS00168

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Cellular Component: GO:0009536 - plastid [Last91]


Created 12-Apr-2011 by Dreher KA , TAIR

Enzymatic reaction of: tryptophan synthase

EC Number:

L-serine + indole <=> L-tryptophan + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: L-tryptophan biosynthesis


Last91: Last RL, Bissinger PH, Mahoney DJ, Radwanski ER, Fink GR (1991). "Tryptophan mutants in Arabidopsis: the consequences of duplicated tryptophan synthase beta genes." Plant Cell 3(4);345-58. PMID: 1840915

Radwanski95: Radwanski ER, Zhao J, Last RL (1995). "Arabidopsis thaliana tryptophan synthase alpha: gene cloning, expression, and subunit interaction." Mol Gen Genet 248(6);657-67. PMID: 7476868

Yin10: Yin R, Frey M, Gierl A, Glawischnig E (2010). "Plants contain two distinct classes of functional tryptophan synthase beta proteins." Phytochemistry 71(14-15);1667-72. PMID: 20701934

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.0 on Wed Jul 29, 2015, biocyc12.