ExplorEnz: EC 2.6.1.123

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2.6.1.123

Accepted name:

4-amino-4-deoxychorismate synthase (2-amino-4-deoxychorismate-forming)

Reaction:

chorismate + 2 L-glutamine + H₂O = 4-amino-4-deoxychorismate + 2 L-glutamate + ammonia (overall reaction)
(1a) 2 L-glutamine + 2 H₂O = 2 L-glutamate + 2 NH₃
(1b) chorismate + NH₃ = (2S)-2-amino-4-deoxychorismate + H₂O
(1c) (2S)-2-amino-4-deoxychorismate + NH₃ = 4-amino-4-deoxychorismate + NH₃

Other name(s):

ADCS (ambiguous); ADC synthase (ambiguous); pabAB (gene names)

Systematic name:

chorismate:L-glutamine aminotransferase (2-amino-4-deoxychorismate-forming)

Comments:

The enzyme, characterized from the bacterium Bacillus subtilis, is a heterodimer. The PabA subunit acts successively on two molecules of L-glutamine, hydrolysing each to L-glutamate and ammonia (cf. EC 3.5.1.2, glutaminase). The ammonia molecules are channeled to the active site of PabB, which catalyses the formation of 4-amino-4-deoxychorismate from chorismate in two steps via the intermediate 2-amino-4-deoxychorismate. cf. EC 2.6.1.85, aminodeoxychorismate synthase.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Schadt, H.S., Schadt, S., Oldach, F. and Sussmuth, R.D. 2-Amino-2-deoxyisochorismate is a key intermediate in Bacillus subtilis p-aminobenzoic acid biosynthesis. J. Am. Chem. Soc. 131 (2009) 3481–3483. [DOI] [PMID: 19275258]
2.	Bera, A.K., Atanasova, V., Dhanda, A., Ladner, J.E. and Parsons, J.F. Structure of aminodeoxychorismate synthase from Stenotrophomonas maltophilia. Biochemistry 51 (2012) 10208–10217. [DOI] [PMID: 23230967]

[EC 2.6.1.123 created 2021]