Pyruvate Dehydrogenase Complex (PDC) Lecture Notes

A series of vocabulary flashcards covering key terms and concepts related to the Pyruvate Dehydrogenase Complex and its metabolic implications.

PDC

Pyruvate Dehydrogenase Complex, an irreversible metabolic gate that converts pyruvate to acetyl-CoA.

Irreversible Reaction

A reaction that cannot be reversed; in the case of PDC, pyruvate cannot be converted back once it becomes acetyl-CoA.

Thioester Bond

A high-energy bond in acetyl-CoA that holds the acetyl group, providing significant energy release upon hydrolysis.

Acetyl-CoA

Generated from pyruvate via PDC, it is a pivotal metabolite that enters the TCA cycle or is utilized for fatty acid synthesis.

Glycolysis

The metabolic pathway that converts glucose into pyruvate, which is then processed by PDC.

Mitochondrial Matrix

The location where the PDC operates, distinct from the cytoplasm where glycolysis occurs.

E1, E2, E3

The three enzymes involved in the PDC, responsible for different steps in the conversion of pyruvate to acetyl-CoA.

Allosteric Regulation

A type of regulation where the activity of an enzyme is modified by the binding of an effector molecule at a site other than the active site.

Phosphorylation

A process that involves the addition of a phosphate group to an enzyme (like E1), which can activate or deactivate the enzyme.

Warburg Effect

The phenomenon where cancer cells favor glycolysis over oxidative phosphorylation, even when oxygen is present, suppressing PDC.

Regulatory Control Point

Key site (like E1) in a pathway where regulation occurs, determining the flow through the pathway based on metabolic needs.

Carbanion

A reactive intermediate formed during the decarboxylation of pyruvate that acts as a nucleophile.

Energetic Favorability

The tendency of a reaction to proceed based on the stability of the reactants and products, influencing the direction of metabolic pathways.

NADH Production

Specifically generated in the PDC by E3, during the reoxidation of lipoamide, marking the only step in which NADH is produced.

Substrate Channeling

The process by which intermediates are passed directly from one enzyme's active site to another within a multienzyme complex, thus enhancing reaction efficiency.

Beriberi

A deficiency of Vitamin B1 (Thiamine) leading to functional PDC failure due to inadequate TPP.

Exam Alert

Key points or concepts highlighted for students to focus on in their study preparations.

Clinical Pearl

Practical insights or recommendations based on clinical experiences, such as administering thiamine before glucose in malnourished patients.