IGP and glutamine

[Silke Beismann]

Hi,
I work on a glutaminase assay, and to optimize the assay I want to find
out two things: 
1. Does anyone know if IGP (imidazole glycerol phosphat) is stable in
aquaous solution ?

2. What is the intracellular level of glutamine in E. coli?

Thanks for your answers!
Silke