CHE 211 Study Guide - Final Guide: Fructose-Bisphosphate Aldolase, Enolase, Carbohydrate
Organic Chemistry 2: Carbohydrate Metabolism
Glycolysis Reaction 1
• This is a phosphorylation step in which the first
molecule of ATP is invested (glucose is converted to
glucose-6-phosphate [G-6-P])
• Substrate glucose is phosphorylated by hexokinase
(enzyme that catalyzed this reaction)
• Product is glucose-6-phosphate
- Source of the phosphoryl group is ATP; at this point, the cell is in energy debt, but it
is necessary to get the reaction started
- Expenditure of ATP early in the pathway works as energ det neessar to get the
pathway started
Glycolysis Reaction 2
o This is the isomerization of G-6-P to F-6-P
o Product of reaction 1 is rearranged to the structural isomer
fructose-6-phosphate by enzyme phosphoglucose
isomerase
o Product (fructose-6-phosphate) has an eposed C-1, no
longer part of the ring structure
- Converts an aldose (G-6-P) to a ketose (F-6-P)
- Examination of the open chain formed reveals that this
isomerization converts an aldose to a ketose
- This is an enol reaction; it occurs in the exact same steps as a conversion of fructose
to glucose that we saw in chapter 16
Glycolysis Reaction 3
▪ This is another phosphorylation reaction where a second molecule of ATP is invested
▪ Substrate fructose-6-phosphate is phosphorylated by the enzyme phosphofructokinase
▪ Product is fructose-1,6-bisphosphate (2
phosphates are on different carbons;
not connected to one another)
- Source of the phosphoryl group is
ATP
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