Allen sandbox 1: Difference between revisions
Justin Allen (talk | contribs) |
Justin Allen (talk | contribs) |
||
| Line 23: | Line 23: | ||
'''Step 1''': The substrate, 2PG, binds to the two <scene name='Cory_Tiedeman_Sandbox_1/Mechanism/4'>Mg2+'s</scene>. The carboxyl group coordinates with the two magnesium ions, which stabilizes the negative charge on the oxygen atom and removes charge from the alpha hydrogen, making it a better leaving group. | '''Step 1''': The substrate, 2PG, binds to the two <scene name='Cory_Tiedeman_Sandbox_1/Mechanism/4'>Mg2+'s</scene>. The carboxyl group coordinates with the two magnesium ions, which stabilizes the negative charge on the oxygen atom and removes charge from the alpha hydrogen, making it a better leaving group. | ||
'''Step 2''': Lys 345 then deprotonates the alpha hydrogen, a reaction which is stabilized by resonance between the carboxyl oxygens and the two Mg ions | '''Step 2''': Lys 345 then deprotonates the alpha hydrogen, a reaction which is stabilized by resonance between the carboxyl oxygens and the two Mg ions and Glu 211 bonded to the hydroxyl group. This creates a carbanion intermediate. | ||
'''Step 3''': An electron transfer reaction then occurs from the C'1 carboxyl oxygen to form a ketone. This removes electrons from the alkene bond between C'1 and C'2 to create an alkene between C'2 and C'3 instead. This allows the C'3 hydroxyl group to deprotonate Glu 211, resulting in the ejection of a water molecule and the product PEP. PEP then | '''Step 3''': An electron transfer reaction then occurs from the C'1 carboxyl oxygen to form a ketone. This removes electrons from the alkene bond between C'1 and C'2 to create an alkene between C'2 and C'3 instead. This allows the C'3 hydroxyl group to deprotonate Glu 211, resulting in the ejection of a water molecule and formation of the product PEP. PEP is then dephosphorylated in the next step of glycolysis to create pyruvate. | ||
Additionally, this mechanism can be inhibited by addition of Fluoride ions, which bond to Mg 2+, thus blocking the substrate (2PG) from binding to the active site of enolase.<ref>{{textbook |author=Voet, Donald; Voet, Judith C.; Pratt, Charlotte W.|title=Fundamentals of Biochemistry: Life at the Molecular Level|edition= 3|pages=500|}}</ref> | Additionally, this mechanism can be inhibited by addition of Fluoride ions, which bond to Mg 2+, thus blocking the substrate (2PG) from binding to the active site of enolase.<ref>{{textbook |author=Voet, Donald; Voet, Judith C.; Pratt, Charlotte W.|title=Fundamentals of Biochemistry: Life at the Molecular Level|edition= 3|pages=500|}}</ref> | ||