Pyruvate Dehydrogenase Complex

What does the pyruvate dehydrogenase complex do

conversion of pyruvate to acetyl CoA

How and where is pyruvate synthesized

glycolysis in the cytoplasm

How is pyruvate transported from the cytoplasm into the mitochondrial matrix

pyruvate transporter

What decarboxylates pyruvate to form acetyl CoA

pyruvate dehydrogenase complex

Pyruvate Dehydrogenase Complex Components

Pyruvate Dehydrogenase (E1)

Dihydrolipoyl Transacetylase (E2)

Dihydrolipoyl Dehydrogenase (E3)

Mechanism of Pyruvate Dehydrogenase

Decarboxylation

Oxidation

Transfer

Reset

Decarboxylation

converts pyruvate to hydroxyethyl-TPP (loss of CO 2)

Oxidation

converts hydroxyethyl-TPP to acetyllipoamide

Transfer

transfers an acetyl group from acetyllipoamide to coenzyme A (CoA)

Reset

oxidation of dihydrolipoamide to lipoamide

Pyruvate Dehydrogenase Complex Core

eight E2 trimers (three E2 subunits=total of 24 E2 subunits)

E2 trimer functional domains

Lipoamide binding domain

E3 interaction domain

Transacetylase domain

What is each E2 trimer surrounded by

a trimer of E1 (8 E1’s total)

E1 trimer components

2 alpha-subunits, 2 beta subunits, and a TPP (thiamine pyrophosphate) prosthetic group

What surrounds the core of eight E2 trimers

12 E3

E3 components

alpha-subunit, beta subunit, and FAD prosthetic group

Beriberi

neurological condition that results from a deficiency of thiamine (vitamin B1), a precursor to TPP

Arsenite Poisoning

Arsenite inhibits the pyruvate dehydrogenase complex by (reversibly) inactivating the dihydrolipoamide (reduced lipoamide) component of E2

How many pyruvate from one glucose

2 pyruvates

How many acetyl CoA from one pyruvate

1

How many acetyl CoA from one glucose

2