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Responsible for turning pyruvate into acetyl CoA:Why is this important?
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Pyruvate dehydrogenase complex (PDC) is responsible for turning pyruvate into acetyl CoA so that it can enter the Citric Acid cycle.
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Overall scheme of the transformation of pyruvate:
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Pyruvate------->decarboxylation---->oxidation----->transfer to CoA---->Acetyl CoAIn other words: Pyruvate----->remove CO2---->remove electrons----->add to CoA-----> Acetyl CoA
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What does PDC need?
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Cofactors
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What are the two types of cofactors?
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Catalytic: cofactors are used by the complex and regenerated hence the name catalytic.Stoichiometric: cofactors are used but not regenerated.
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Fat soluble vitamins:
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Fat soluble: Vitamin A, D, E, K
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Water Soluble vitamins
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Water soluble: B complex and C Thiamine (B1) Riboflavin (B2) Pantothenic acid (B5) Niacin (B3) Lipoic acid
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Examples of catalytic cofactors:
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Thiamine (B1)Lipoic acidRiboflavin (B2): used as FAD
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Examples of stoichiometric cofactors:
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Pantothenic acid (B5): used as coenzyme ANiacin (B3): used as NAD+
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Explain significance of pyruvate to acetyl CoA:
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Pyruvate--->Acetyl CoA is irreversible. Once it becomes acetyl CoA, it can not go backwards and form pyruvate
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Explain PDH complex of 3 enzymes
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PDH is a complex made up of three enzymes 1. Pyruvate Dehydrogenase E1 catalyzes steps 1-22: Dihydrolipoyl Transacetylase E2 catalyzes step 33: Dihydrolipoyl Dehydrogenase E3 catalyzes steps 4-5
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What is PDH inhibited by? examples
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PDH Complex is inhibited by HIGH ENERGY
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What is PDH stimulated by?
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PDH is stimulated by LOW ENERGY
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Phosphorylates pyruvate dehydrogenase E1 (PDH) making it less active.
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Pyruvate dehydrogenase kinase
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Kinase=halt _________
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PDH's activity
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When the body needs energy, there are a lot of _________.What will this do?
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ADP floating around. ADP will inhibit kinase activity.
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