way , ▁a ▁trans ald ol ase ▁removes ▁the ▁first ▁ 3 ▁carbon ▁mole cules ▁of ▁sed o he pt ul ose ▁ 7 - ph osph ate ▁and ▁places ▁them ▁onto ▁a ▁g ly cer al de hy de ▁ 3 - ph osph ate . ▁The ▁trans ald ol ase ▁util izes ▁a ▁Schiff ▁base ▁to ▁perform ▁a ▁reverse ▁al d ol ▁reaction ▁and ▁a ▁forward ▁al d ol ▁reaction ▁in ▁its ▁mechanism , ▁generating ▁an ▁er yth rose ▁ 4 - ph osph ate ▁and ▁f ruct ose ▁ 6 - ph osph ate . ▁The ▁er yth rose ▁ 4 - ph osph ate ▁is ▁an ▁important ▁intermediate ▁in ▁the ▁Pent ose ▁Ph osph ate ▁Path way ▁because ▁it ▁is ▁then ▁used ▁in ▁the ▁final ▁non - ox id ative ▁step ▁of ▁the ▁path way . ▁ ▁The ▁final ▁non - ox id ative ▁step ▁of ▁the ▁path way ▁is ▁a ▁trans ket ol ase ▁reaction . ▁A ▁trans ket ol ase ▁util izes ▁a ▁th iam ine ▁py roph osph ate , ▁or ▁T PP ▁c of actor , ▁to ▁break ▁the ▁unf avor able ▁bond ▁between ▁the ▁carbon ▁in ▁a ▁car b ony l ▁and ▁the ▁alpha ▁carbon . ▁T PP ▁attacks ▁a ▁x yl ul ose ▁ 5 - ph osph ate ▁mole c ule ▁and ▁facil it ates ▁the ▁cle av age ▁of ▁the ▁bond ▁between ▁the ▁C 2 ▁( car b ony l ▁carbon ) ▁and ▁the ▁C 3 ▁( alpha ▁carbon ), ▁where