PDH COMPLEX

mitochondrial matrix

Pyruvate Oxidation occurs in the ______

mitochondrial pyruvate carrier

Under aerobic conditions, in eukaryotes, the pyruvate generated from glucose is transported into the mitochondrial matrix for oxidation via the _________

decarboxylated, acetyl CoA, PDH

Under aerobic conditions, the pyruvate generated from glucose is oxidatively _______ to form ______ , using the _____ complex

pyruvate dehydrogenase component, dihydrolipoyl transacetylase, dihydrolipoyl dehydrogenase

The PDH complex contains 3 enzymes:

• E1: ______

• E2: ______

• E3: _______

TPP, oxidative decarboxylation of pyruvate

pyruvate dehydrogenase component : E1

• Prosthetic group: ______

• RXN catalyzed: _____

Lipoamide, transfer of acetyl group to CoA

dihydrolipoyl transacetylase: E2

• Prosthetic group: ______

• RXN catalyzed: _____

FAD, regen of oxidized form of lipoamide

dihydrolipoyl dehydrogenase: e3

• Prosthetic group: ______

• RXN catalyzed: _____

Catalytic

______ coenzymes:

• modified but regenerated in each reaction cycle

Stoic

_____ coenzymes:

• used in only one reaction because they are the components of products of the reaction

TPP, lipoamide, CoA, FAD, NAD+

List the 5 coenzymes that make up the pyruvate dehydrogenase complex

CoA, NAD+

what are the 2 STOIC coenzymes?

TPP, lipoamide, FAD

what are the 3 CATALYTIC coenzymes?

TPP

decarboxylates pyruvate, yielding hydroxyethyl-TPP

lipoamide

accepts hydroxyethyl carbocation from TPP as acetyl group

CoA

accepts acetyl group from lipoamide

FAD

Accepts pair of electrons from reduced lipoamide

NAD+

Accepts pair of electrons from reduced FADH2

irr

formation of acetyl CoA from pyruvate

• rev or irr?

citric acid cycle, fatty acids

what are the 2 fates of acetyl CoA?

• metabolism by ____

• incorporation into ______

E2

acetyl CoA inhibits the _____ component by binding DIRECTLY

E3

NADH inhibits the ______ component

NADH, acetyl CoA, glucose

HIGH concentrations of _____ and _______ inform the enzyme that the energy needs of the cell have been met and there’s no need to make these two compounds

• this spares _____

more

Complete oxidation of glucose via respiration is _____ efficient than incomplete oxidation through fermentation

doesn’t , 2

Fermentation _____ fully oxidize glucose

• _____ ATP produced earlier in glycolysis

32

Complete oxidation of glucose results in about _____ ATP being synthesized

acyl groups, pantothenate

Coenzyme A (CoA) is a carrier of ______ derived from the vitamin ________

TPP, hydroxyethyl-TPP, E1

PDH Step 1: Decarboxylation

• Pyruvate combines with _____ and is then decarboxylated to yield _____

• _____ catalyzes the decarboxylation

acetyl group , E1, acetyllipoamide

PDH Step 2:Oxidation and transfer to lipoamide

• The hydroxyethyl group attached to TPP is oxidized to form an _______ while being simultaneously transferred to lipoamide,

• This reaction, catalyzed by the ___, yields _______.

CoA, acetyl CoA, E2

PDH Step 3: Formation of Acetyl CoA

• The acetyl group is transferred from acetyllipoamide to _____ to form _____

• _____ catalyzes this reaction.

dihydrolipoamide, E3, disulfide, FAD

PDH Step 4: Regeneration of oxidized lipoamide

• To participate in another reaction cycle, ______ must be reoxidized.

• This reaction is catalyzed by ______

• Lipoamide is oxidized by this enzyme’s _____ bond and the _____ cofactor .

E3, E3, FAD, NADH, H+

PDH Step 5: Regeneration of oxidized E3

• To participate in another reaction cycle, ____ itself must be reoxidized.

• This reaction catalyzed by ______

• Electrons move to ____to form FADH2.

  • Electrons move from FADH2 to NAD+ to form _____ and ______

• The enzyme is restored to its oxidized state.

PDH, acetyl CoA, CO2, NADH

In order for pyruvate to enter the citric acid cycle, it must undergo oxidative decarboxylation catalyzed by the _____ complex, which yields ________, ______, and _____.

E1, PDK

______ is a key site of regulation in the PDH complex

• _____ phosphorylates and INACTIVATES this enzyme