an acid:ammonia ligase (amide synthetase) forming L-asparagine and L-glutamate from L-aspartate and L-glutamine, with the concomitant cleavage of ATP to AMP and pyrophosphate. Under nonphysiological conditions, the mammalian enzyme can use ammonia as the nitrogen donor. Asparagine ligase also displays a glutaminase-like activity. Syn: asparagine synthetase.