Pyruvate Dehydrogenase complex

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PDC
one of the largest multienzyme,supramolecular machines-found in pro/eukaryotes and serves strategic roles in metabolism.
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Mitochondrium-Matrix
internal space containing enzymes of the TCA cycle and oxidative decarboxylation of pyruvate.
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Inner membrane
large surface by invaginations (folds-Cristae), proteins,electrochemical gradient of H+ (drives pyruvate &phosphate uptake).
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Outer membrane
channel protein(porin), molecules up to 5 KDA can enter the intermembrane space.
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What is pyruvate Dehydrogenase
the irreversable link from glycolosis to the TCA cycle is pyruvate dehydrogenase. this is a REDOX reaction called an oxidative decarboxylation.
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Acetate unit within pyruvate
activated by linking to coA so that it can undergo further reactions.
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Acetyl CoA
look at drawing in the book and name each section ie- adenosine diphospahte, acetate.
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Mitochondrial oxidative decarboxylation of pyruvate
Irreverable reaction in mitochondrium (cytosol of bacteria). commits (binds) the carbon atoms of carbohydrates and amino acids to oxidation via the TCA cycle OR to the synthesis of fatty acids.
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Mitochondrial oxidative decarboxylation of pyruvate (REACTION)
occurs only if ATP is needed or Two-carbon fragments are required for fatty acid biosynthesis. Controlled allosterically (site on E2 where a molecule binds N-Co and affects function of active site) and by phosphoraltaion
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3 reactions of pyruvate dehydrogenase multienzyme complex
decarboxylation of pyruvate (3-carbons) to a (2-carbon) alcohol. 2/ oxidation of the alcohol to an acid (acetic acid) reduction of NAD+ to NADH (electron capture). 3/ esterification to coenzyme A=acetyl coA, TCA cycle or fatty acid synthesis.
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Multi-subunit complex
E1-Pyruvate dehydrogenase. E2- Dihydrolipoamide acetyltransferase. E3- Dihydrolipoamide dehydrogenase.
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Regualtion of the entry to TCA cycle
regulated allosterically:inhibited by NADH & Acetyle CoA,activated by NAD+ and CoA-SH.
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what can animals not do with acetyl?
animals cannot convert acetyl back into glucose - carbon of glucose is commited to 1/ oxidation to CO2 2/ incorporation into lipid.
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Inhibition of Pyruvate Dehydrogenase
inhibited by phosphoralation on E1- PDH kinase activated by ATP, NADH and acetyl CoA., 2/ PDH kinase inhibited by ADP and pyruvate. 3/ PDH Phosphatase activated by an increase in [Ca2+].
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Advantage of a multienzyme complex
non-covalently associated enzymes that catalyse two or more sequencial steps in a metabolic pathway., used for metabolic channelling. direct transfer of a metabolite from 1 enzyme to another, avoids dilution of metabolitein AQ enviro.. increase rate.
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Diffusion of substance
not rate- limiting. A seriouse of chemical intermediates remain bound to enzyme molecules
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6 Major components of Human PDC
pyruvate dehydrogenase E1. Dihydrolipoyl acetyltransferase E2. Dihydrolipoyl dehydrogenase E3. E3 binding protein (E3BP).
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Other cards in this set

Card 2

Front

internal space containing enzymes of the TCA cycle and oxidative decarboxylation of pyruvate.

Back

Mitochondrium-Matrix

Card 3

Front

large surface by invaginations (folds-Cristae), proteins,electrochemical gradient of H+ (drives pyruvate &phosphate uptake).

Back

Preview of the back of card 3

Card 4

Front

channel protein(porin), molecules up to 5 KDA can enter the intermembrane space.

Back

Preview of the back of card 4

Card 5

Front

the irreversable link from glycolosis to the TCA cycle is pyruvate dehydrogenase. this is a REDOX reaction called an oxidative decarboxylation.

Back

Preview of the back of card 5
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