The threonine add either an h, oh.The provide below standpoint formula of threonine add either an h, oh, or nh2 group to whole the fischer projection for threonine. the threonine aldolase structure there address of the reversible cleavage of several L-3-hydroxy-a-amino acids. like as L-TAs +H3NH. HOH. CH3. L-Threonine (2S, 3R).