1. 2 Important Features of Enzymes
Enzymes are proteins used in chemical reactions. In the reactions, enzymes act as catalysts. They function to speed up chemical reactions without using the enzymes themselves. The catalysts are neither the reactor nor the product. The first feature discussed in the text is the energy of the reaction. Catalysts will not change the energy of any reaction. For example, a non-catalyzed reaction and a catalyst reaction will both have the same equilibrium. Another feature is the activation energy. This is the free energy of activation where the catalyst reaction reaches the transition state. All catalysts lower activation energies of reactions.
By lowering the energy molecules will reach the necessary energy level where the reaction ultimately occurs. 2. Protein Catalysts in the First 2 Steps of Fructose Metabolism in the Liver Initially the catabolism that takes place in our body with fructose is the process called fructolysis. Fructokinase is found in the liver and starts the breakdown of fructose. Fructokinase produces fructose 1-phosphate, ending step one in the metabolism of fructose in the liver. In step 2, aldolase B (another enzyme) converts fructose 1-phosphate into dishydroxyacetone phosphate (DHAP) and glyceraldehyde. These help produce energy for the body. If the enzyme was unable to metabolize fructose it would be impossible to ingest and the host of the enzyme would be unable to produce energy.
3. Induced Fit Model
4. Substrate Acted on by Aldolase B
The specific substrate used by Aldolase B is fructose 1-phsphatee (F1P). Once the substrate is formed and is converted into DHAP and glyceraldehyde glycolysis is entered to form ATP (energy).
5. Role of Aldolase B in the metabolism of Fructose
a. Pathways the products of aldolase B enter
6. Deficiency in aldolase B responsible for HFI
Hereditary fructose intolerance (HFI) is a hereditary health condition in where the person is unable to digest the sugar fructose. Foods containing fructose like honey or fruit can lead to nausea, vomiting, bloating, diarrhea, or abdominal pain for someone who has HFI. a. Amount of substrate of aldolase B is impacted by the deficiency b. Role of substrate in producing symptoms of HFI
Aldolase B is needed to breakdown fructose. Without the Aldolase B, we are unable to change metabolize glycogen into glucose. When the body cannot metabolize glycogen or fructose hypoglycemia occurs and the fructose will build up in the liver. Symptoms include severe abdominal pain, vomiting, and hypoglycemia following ingestion of fructose or other sugars metabolized through fructose-1-phosphate. Prolonged fructose ingestion can lead to hepatic/renal failure and death.