▁at ▁P H ▁ 7 . 5 ▁and ▁ 3 7   ° C , ▁research ers ▁have ▁suggested ▁that ▁the ▁comp ound ▁is ▁ch anne led ▁from ▁amid oph osph or ib os yl trans fer ase ▁to ▁G AR ▁synth et ase ▁in ▁v ivo . ▁ ▁P RA ▁+ ▁G ly c ine ▁+ ▁ATP ▁→ ▁G AR ▁+ ▁AD P ▁+ ▁Pi ▁ ▁The ▁third ▁is ▁catal yz ed ▁by ▁ph osph or ib os yl gly cin am ide ▁form yl trans fer ase . ▁ ▁G AR ▁+ ▁f TH F ▁→ ▁f G AR ▁+ ▁TH F ▁ ▁The ▁fourth ▁is ▁catal yz ed ▁by ▁ph osph or ib os yl form yl gly cin am id ine ▁synth ase . ▁ ▁f G AR ▁+ ▁L - G l ut am ine ▁+ ▁ATP ▁→ ▁f G AM ▁+ ▁L - G l ut am ate ▁+ ▁AD P ▁+ ▁Pi ▁ ▁The ▁fifth ▁is ▁catal yz ed ▁by ▁A IR ▁synth et ase ▁( F G AM ▁cycl ase ). ▁ ▁f G AM ▁+ ▁ATP ▁→ ▁A IR ▁+ ▁AD P ▁+ ▁Pi ▁+ ▁H 2 O ▁ ▁The ▁sixth ▁is ▁catal yz ed ▁by ▁ph osph or ib os yl am ino im id az ole ▁car box yl ase . ▁ ▁A IR ▁+ ▁CO 2 ▁→ ▁CA IR ▁+ ▁ 2 H + ▁ ▁The ▁sevent h ▁is ▁catal yz ed ▁by ▁ph osph or ib os yl am ino