Transferases;
Transferring nitrogenous groups;
Transaminases
BRITE hierarchy

chorismate:L-glutamine aminotransferase

chorismate + L-glutamine = 4-amino-4-deoxychorismate + L-glutamate (overall reaction) [RN:R01716];
(1a) L-glutamine + H2O = L-glutamate + NH3 [RN:R00256];
(1b) chorismate + NH3 = 4-amino-4-deoxychorismate + H2O [RN:R05552]

R00256 R01716 R05552
Reaction

chorismate [CPD:C00251];
L-glutamine [CPD:C00064];
H2O [CPD:C00001];
NH3 [CPD:C00014]

The enzyme is composed of two parts, a glutaminase (PabA in Escherichia coli) and an aminotransferase (PabB). In the absence of PabA and glutamine (but in the presence of Mg2+), PabB can convert ammonia and chorismate into 4-amino-4-deoxychorismate. PabA converts glutamine into glutamate only in the presence of stoichiometric amounts of PabB. In many organisms, including plants, the genes encoding the two proteins have fused to encode a single bifunctional protein. This enzyme is coupled with EC 4.1.3.38, aminodeoxychorismate lyase, to form 4-aminobenzoate. cf. EC 2.6.1.123, 4-amino-4-deoxychorismate synthase (2-amino-4-deoxychorismate-forming).

EC 2.6.1.85 created 2003 as EC 6.3.5.8, transferred 2007 to EC 2.6.1.85, modified 2022