Patologia e fisiopatologia generale - Pyruvate Dehydrogenase

Aggiornato il 21/03/2026

di Daniele

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Appunti di Patologia e fisiopatologia generale della professoressa Castoria su Pyruvate Dehydrogenase con analisi dei seguenti argomenti: ciclo di Krebs, compartimenti mitocondriali, Pyruvate …

Esame Patologia e Fisiopatologia Generale

Facoltà Medicina e chirurgia

Dal corso del Prof. Castoria Gabriella

Università Università degli studi della Campania "Luigi Vanvitelli"

A.A. 2012-2013

28 pagine

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Pyruvate dehydrogenase

Localization of Krebs Cycle: The Krebs Cycle occurs in the matrix of mitochondria, while glycolysis takes place in the cytosol of cells. Pyruvate enters the mitochondrion to be metabolized further.

Mitochondrial compartments

The mitochondrion is comprised of several compartments:

Outer membrane: Contains large channels and is leaky to ions and small molecules.
Intermembrane space: The space between the inner and outer membranes.
Inner membrane: Contains infoldings called cristae, which house components of the respiratory chain and ATP Synthase. It acts as the major permeability barrier and contains transport catalysts, including a carrier protein for pyruvate entry into the matrix.
Matrix: Contains the Pyruvate Dehydrogenase complex, Krebs Cycle, and enzymes for fatty acid oxidation and amino acid metabolism.

Pyruvate dehydrogenase complex

The Pyruvate Dehydrogenase catalyzes the oxidative decarboxylation of pyruvate to form acetyl-CoA, with a free energy change (G) of -33.4 kJ/mol. It is a large complex consisting of multiple copies of three enzymes: E₁, E₂, and E₃.

Core of the complex: Consists of 60 copies of E₂.
Periphery of the complex: Includes 30 copies of E₁ (a tetramer with α and β subunits), 12 copies of E₃ (a homodimer), and 12 copies of an E₃ binding protein linking E₃ to E₂.

Pyruvate dehydrogenase subunits

Enzyme	Abbreviated	Prosthetic Group
Pyruvate Dehydrogenase	E₁	Thiamine pyrophosphate (TPP)
Dihydrolipoyl Transacetylase	E₂	Lipoamide
Dihydrolipoyl Dehydrogenase	E₃	FAD

The Pyruvate Dehydrogenase Complex requires five different coenzymes: TPP, FAD, CoA, NAD, and lipoate. Four of these coenzymes are derived from vitamins: Thiamin (TPP), riboflavin (FAD), pantothenate (CoA), and niacin (NAD).

The E. coli Pyruvate Dehydrogenase Complex has a molecular weight of approximately 4600 kDa and a diameter of about 300 Å.

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