Ken Engle SANDBOX: Difference between revisions

The active site of PDH in Zymomonas mobilis consists of Glu50, Glu 473, Asp27, and His114 <ref>PMID: 20099870 </ref>. Hydrogen bonding occurs between the substrate and Asp27, His114, and Thr72. Yeast active site residues are similar. In the catalytic step of the reaction mechanism, <scene name='Ken_Engle_SANDBOX/Glu_473/1'>Glu473</scene> donates a proton to the pyruvate. The scene shows the close proximity of this residue to the pyruvate. The negative charge of the Glu residue following the protonation of the substrate leads to the destabilization of the pyruvate carboxylate group. Next the carboxyl group leaves. Following decarboxylation in the final step of the mechanism, release of acetaldehyde, a proton is transferred to the Glu473 residue from a cofactor. After the protonation in a concerted step, a water molecule donates a proton to the substrate while receiving a proton from Glu473. As the proton is taken from the substrate, the electrons move to form a carbonyl, which leads to the release of the acetaldehyde<ref>PMID: 20099870 </ref>.