at ase ▁( FB P ase ) ▁and ▁in os it ol ▁poly ph osph ate ▁ 1 - ph osph at ase . ▁ ▁Catal yt ic ▁mechanism ▁▁ ▁It ▁was ▁previously ▁reported ▁that ▁the ▁hydro ly s is ▁of ▁in os it ol ▁mon oph osph ate ▁was ▁catal yz ed ▁by ▁I MP ase ▁through ▁a ▁ 2 - m agn es ium ▁ion ▁mechanism . ▁ ▁However ▁a ▁recent ▁ 1 . 4 ▁A ▁resolution ▁cry stal ▁structure ▁shows ▁ 3 ▁mag nes ium ▁ ions ▁coordin ating ▁in ▁each ▁active ▁binding ▁site ▁of ▁the ▁ 2 ▁dim ers , ▁supporting ▁a ▁ 3 - m agn es ium ▁ion ▁mechanism . ▁The ▁mechanism ▁for ▁hydro ly s is ▁is ▁now ▁thought ▁to ▁proceed ▁as ▁such : ▁the ▁en zym e ▁is ▁activ ated ▁by ▁a ▁mag nes ium ▁ion ▁binding ▁to ▁binding ▁site ▁I , ▁containing ▁three ▁water ▁mole cules , ▁and ▁stabil ized ▁by ▁the ▁negative ▁charges ▁on ▁the ▁car box yl ates ▁of ▁G lu 7 0 ▁and ▁Asp 9 0 , ▁and ▁the ▁car b ony l ▁of ▁I le 9 2 . ▁ ▁Another ▁mag nes ium ▁ion ▁then ▁co oper atively ▁bind s ▁to ▁binding ▁site ▁ 2 , ▁which ▁has ▁of ▁car box yl ates ▁of ▁Asp 9 0 , ▁Asp 9 3 , ▁Asp 2 2 0 , ▁and ▁three ▁water ▁mole cules , ▁one ▁of ▁which ▁is ▁shared ▁by ▁binding ▁site ▁ 1 . ▁Then , ▁a ▁third ▁mag nes