Western Governors University
Hereditary Fructose Intolerance
Metabolism is the process of cellular respiration. It involves three steps, 1) glycolysis, 2) the citric acid or Krebs cycle and 3) electron transport system. The glycolytic pathway or glycolysis is a metabolic process that leads to the formation of the energy source adenosine triphosphate (ATP) in the body. ATP is essential to the cell and the cellular processes used by the cell. The first step, glycolysis is the process by which each molecule of glucose is converted to two pyruvate molecules, creating two ATPs and two nicotinamide adenine dinucleotide (NADH).
NADH is also converted to four ATPs during the electron transport chain.
An enzyme is a protein or other substance that will bind to a substrate, or substance that needs to be changed, to create a new, different, product. This product then becomes the next substrate for another enzyme and so on. An enzyme lowers the activation energy of a substance and acts as a catalyst (Hudon-Miller, 2012).
The process of metabolism of sugar (sucrose) includes two monosaccharaides, glucose and fructose. Glucose and fructose both go through glycolysis, however, fructose if first undergoes a conversion to glyceraldehyde and dihydroxyacetone phosphate (DHAP). Fructose is almost completely metabolized in the liver and is used towards replenishing glycogen in the liver and in triglyceride synthesis. There are three steps to fructose breakdown by the liver. First, the fructose has a phosphate added by the enzyme fructokinase to form fructose-1-phosphate. Next, the 6-carbon fructose is split into the 3-carbon molecules glyceraldehyde and DHAP by the enzyme aldolase B. Lastly, glyceraldehyde is then phosphorylated again by another enzyme so that it can enter the glycolytic pathway (New World Encyclopedia, n.d.).
In Hereditary Fructose Intolerance (HFI) the body lacks the enzyme needed to break down fructose in the liver. This enzyme,
References: Energy, ATP, and Enzymes. Retrieved on February 28, 2013 from http://www.uic.edu/classes/bios/bios100/lectures/enzymes.htm Genetic People. (2011). Fructose 1-Phosphate Aldolase Deficiency (Fructose Intolerance). Retrieved on February 26, 2013 from http://geneticpeople.com/?p=882. Hudon-Miller, Sarah. 2012. Cori Cycle. Video retrieved from http://www.youtube.com/watch?v=gWXDNBiLva4&feature=youtu.be. Hudon-Miller, Sarah. 2012. Enzymes and Fructose Breakdown. Video retrieved from http://www.youtube.com/watch?v=eRepj3rA4AQ&feature=youtu.be. Hudon-Miller, Sarah. 2012. Overview of Metabolism. Video retrieved from http://www.youtube.com/watch?v=89Viv2IustM&feature=youtu.be. Wikipedia. 2013. Coenzyme Q10. Retrieved on March 5, 2013 from http://en.wikipedia.org/wiki/Coenzyme_Q10 Wikipedia. 2013. Fructose-1-Phosphate. Retrieved on February 28, 2013 from http://en.wikipedia.org/wiki/Succinate Wikipedia. 2013. Succinic acid. Retrieved on February 28, 2013 from http://en.wikipedia.org/wiki/Succinate Wikipedia. 2013. The Citric Acid Cycle. Retrieved on February 28, 2013 from http://en.wikipedia.org/wiki/Citric_acid_cycle