This enzyme has 2 functions: it catalyzes the production of glutamine and 4-aminobutanoate (gamma-aminobutyric acid, GABA), the latter in a pyridoxal phosphate-independent manner . Essential for proliferation of fetal skin fibroblasts. "Glutamine synthetase isolated from human brain: octameric structure and homology of partial primary structure with human liver glutamine synthetase."
Boksha I.S., Schonfeld H.J., Langen H. Biokhimiia 67:1012-1020(2002) "Glutamine synthetase is essential for proliferation of fetal skin fibroblasts."
Vermeulen T., Goerg B., Vogl T. Arch. Biochem. Biophys. 478:96-102(2008)