Enables GMP synthase (glutamine-hydrolyzing) activity. Involved in GMP biosynthetic process. Predicted to be located in cytoplasm. Predicted to be active in cytosol. Is expressed in several structures, including alimentary system; brain; genitourinary system; respiratory system; and sensory organ. Orthologous to human GMPS (guanine monophosphate synthase). [provided by Alliance of Genome Resources, Apr 2022]