Inorganic Acid Lab Report

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Arsenate can replace inorganic phosphate in step 6 of glycolysis that produces 1,3-bisphosphoglycerate instead of glyceraldehyde 3-phospahte. This yields 1-arseno-3-phosphoglycerate instead, which is unstable and quickly hydrolyzes, forming the next intermediate in the pathway, 3-phosphoglycerate. This is the same product that is normally formed in step 7. This is a problem because the product forms before it should and therefore does not reach the enzyme so the energy released cannot be harvested to generated ATP. Arsenate wastes energy by the uncoupling phosphotransfer reaction so its very POISONOUS. However, glycolysis still proceeds. Arsenate can then also inhibit the conversion of pyruvate into acetyl-CoA, blocking the Krebs cycle and therefore resulting in further loss of ATP.…show more content…
Nevertheless, small changes in enzyme activities and affinities could be observed. For instance, arsenate can cause hexokinase to work slower. Next Slide (with graph)- Attached is the graph that shows the difference between the enzyme activities when phosphorus is used and when arsenic is used. As you can tell, the enzyme activity decreases when arsenic is added. At the level of the Krebs cycle, it primarily inhibits enzymes that require lipoic acid as a cofactor, such as pyruvate and alpha-ketogluterate dehydrogenase. This then inhibits the Krebs Cycle, which stops the production of reduced NAD (NADH). Therefore, arsenic poisoning kills by allosteric inhibition of essential metabolic enzymes, leading to death from multi-organ

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