Phosphoglucoisomerase: Difference between revisions
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The proposed reaction mechanism of PGI for the reversible conversion of glucose-6-phosphate to fructose 6-phosphate involves an acid/base catalysis by the enzyme.<ref> Voet D, Voet J, and Pratt C. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. Print.</ref> | The proposed reaction mechanism of PGI for the reversible conversion of glucose-6-phosphate to fructose 6-phosphate involves an acid/base catalysis by the enzyme.<ref> Voet D, Voet J, and Pratt C. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. Print.</ref> | ||
'''Step 1''' The substrate binds to the enzyme. | '''Step 1.''' The substrate binds to the enzyme. | ||
'''Step 2''' The residue Lys518 (or His388b) acts as an enzymatic acid catalyzing the opening of the ring. | '''Step 2.''' The residue Lys518 (or His388b) acts as an enzymatic acid catalyzing the opening of the ring. | ||
'''Step 3''' Conserved Glu357 abstracts the acidic proton from C2 forming a cis-enendiol intermediate. | '''Step 3.''' Conserved Glu357 abstracts the acidic proton from C2 forming a cis-enendiol intermediate. | ||
'''Step 4''' Glu357 donates back the proton at the C1 position. | '''Step 4.''' Glu357 donates back the proton at the C1 position. | ||
'''Step 5''' Lys518 (or His388b) abstracts back the proton from the sugar ring oxygen, resulting in a ring closure, to give the product. | '''Step 5.''' Lys518 (or His388b) abstracts back the proton from the sugar ring oxygen, resulting in a ring closure, to give the product. | ||
[[Image:Mech.png]] | [[Image:Mech.png]] | ||
