Reaction: chorismate + 2 L-glutamine + H2O = 4-amino-4-deoxychorismate + 2 L-glutamate + NH3 (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)
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 component is a glutamine amidotransferase that hydrolyses glutamine to glutamate, forming ammonia, which is channeled to the PabB active site. PabB 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, CAS registry number:
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. [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. [PMID: 23230967]