Glycolysis Enzymes
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The first phase of glycolysis is sometimes referred to as the "investment phase", where ATP is consumed to set up later, energy generating steps. The first step of the pathway is the conversion of glucose to glucose-6-phosphate by either [[Kyle_Schroering_Sandbox|hexokinase or glucokinase]]. | The first phase of glycolysis is sometimes referred to as the "investment phase", where ATP is consumed to set up later, energy generating steps. The first step of the pathway is the conversion of glucose to glucose-6-phosphate by either [[Kyle_Schroering_Sandbox|hexokinase or glucokinase]]. | ||
| - | Glucose-6-phosphate isomerizes to fructose-6-phosphate; this reaction is catalyzed by [[Stancu_Phosphoglucoisomerase_Sandbox_1|phosphoglucoisomerase]]. This isomerization allows for the creation of two, three carbon sugars as a product. [[Zach_Westrick_Sandbox|Phosphofructokinase]] catalyzes the second phosphorylation reaction, and is the most highly regulated step of the pathway. | + | Glucose-6-phosphate isomerizes to fructose-6-phosphate; this reaction is catalyzed by [[Stancu_Phosphoglucoisomerase_Sandbox_1|phosphoglucoisomerase]]. This isomerization allows for the creation of two, three carbon sugars as a product. [[Zach_Westrick_Sandbox|Phosphofructokinase]] catalyzes the second phosphorylation reaction, and is the most highly regulated step of the pathway. [[Austin_Drake_Sandbox|Aldolase]] catalyzes the retro-aldol cleavage of fructose 1,6-bisphosphate into two three carbon phosphosugars, dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. The interconversion of these two sugars is catalyzed by [[Christian_Krenk_Sandbox|triose phosphate isomerase]], also referred to as TIM. |
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| + | The next five reactions are the "payoff" phase of glycolysis, where energy in the forms of ATP and NADH is generated. All of the subsequent reactions happen twice (once for each of the two glyceraldehyde 3 phosphate molecules generated from glucose). First, [[Nathan_Line_sandbox_3|glyceraldehyde-3-phosphate dehydrogenase]] oxidizes glyceraldehyde-3-phosphate, transferring a hydride to NAD+, generating NADH and H+. | ||
Revision as of 19:26, 1 April 2010
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The Enzymes of Glycolysis
Glycolysis is a key metabolic pathway for organisms. In it, glucose is converted into two pyruvate molecules. The process includes ten enzymes, described in further detail on the linked pages.
The first phase of glycolysis is sometimes referred to as the "investment phase", where ATP is consumed to set up later, energy generating steps. The first step of the pathway is the conversion of glucose to glucose-6-phosphate by either hexokinase or glucokinase. Glucose-6-phosphate isomerizes to fructose-6-phosphate; this reaction is catalyzed by phosphoglucoisomerase. This isomerization allows for the creation of two, three carbon sugars as a product. Phosphofructokinase catalyzes the second phosphorylation reaction, and is the most highly regulated step of the pathway. Aldolase catalyzes the retro-aldol cleavage of fructose 1,6-bisphosphate into two three carbon phosphosugars, dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. The interconversion of these two sugars is catalyzed by triose phosphate isomerase, also referred to as TIM.
The next five reactions are the "payoff" phase of glycolysis, where energy in the forms of ATP and NADH is generated. All of the subsequent reactions happen twice (once for each of the two glyceraldehyde 3 phosphate molecules generated from glucose). First, glyceraldehyde-3-phosphate dehydrogenase oxidizes glyceraldehyde-3-phosphate, transferring a hydride to NAD+, generating NADH and H+.
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