Show how to bring about each step in the following synthesis.
CHEM 372 Week 3 Notes 4/12/16 Reaction 7 1,3-BPG to 3PG using PGK as the enzyme Slightly exergonic but is the breaking even point of Glycolysis Close to equilibrium Uses protein dynamics to drive reaction. Push Pull reaction mech. Forces phosphates together till they touch and react. Swap phosphates. Similar to hexokinase mechanism Active site of enzyme has Lysine that points towards BPG phosphate o Pulls electron density away from phosphate group on BPG o Oxygen on ADP phosphate attacks electrophilic phosphate on BPG o Transition state is the most energetically rich molecule o Lysine on enzyme stabilizes TS to speed up reaction o Substrate level phosphorylation: phosphate group is transferred from metabolite directly onto ADP o Oxidative phosphorylation: ADP + P -i---ATP Reaction 8 o 3PG ---- 2PG, enzyme is PGM o At the active site, phosphohistidine. Absolutely required for activity o Phosphohistidine attacked by deprotonated 2’-OH o Histidine attacks 3’-PO and 3’-O deprotonates and + 3 acid (B-H ) nd o 2 step is the rate-limiting step o Intermediate (2,3-BPG) just hangs out in active site for a while, sometimes it dissociates from the enzyme o Cannot synthesize phosphohistidine complex o Red Blood Cells harness 2,3-BPG to lower the affinity for O2 – regulator of hemoglobin (alloste