explain why glucose 1,6 bisphosphate would not be able to go through the aldolase reaction.
Glucose 1,6-bisphosphate (G1,6BP) is a key intermediate in the glycolysis pathway, and it is an important molecule for energy production in cells. The aldolase reaction is a crucial step in glycolysis, where fructose 1,6-bisphosphate is cleaved into two three-carbon molecules, glyceraldehyde 3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP).
However, in the case of glucose 1,6-bisphosphate, it cannot go through the aldolase reaction directly. This is because aldolase enzyme specifically recognizes and acts on fructose 1,6-bisphosphate, not glucose 1,6-bisphosphate.
To understand why this occurs, we need to consider the structure of both glucose 1,6-bisphosphate and fructose 1,6-bisphosphate. Both molecules have a phosphate group attached to the carbon-1 position, but the difference lies in the other end of the molecule.
Glucose 1,6-bisphosphate has a glucose moiety attached to the carbon-6 position, while fructose 1,6-bisphosphate has a fructose moiety attached there. The aldolase enzyme is specifically designed to recognize and bind to the fructose moiety of fructose 1,6-bisphosphate, allowing for the catalysis of the aldolase reaction.
Due to the structural difference between glucose and fructose moieties, aldolase enzyme cannot effectively recognize and bind to glucose 1,6-bisphosphate. Therefore, glucose 1,6-bisphosphate cannot undergo the aldolase reaction directly.
In order for glucose 1,6-bisphosphate to enter the glycolysis pathway, it needs to be converted into fructose 1,6-bisphosphate through the action of the enzyme phosphofructokinase, which transfers a phosphate group from ATP to glucose 1-phosphate.
Once fructose 1,6-bisphosphate is formed from glucose 1,6-bisphosphate, it can then proceed through the aldolase reaction, ultimately leading to the generation of the two three-carbon molecules, glyceraldehyde 3-phosphate and dihydroxyacetone phosphate.