Oxidative Decarboxylation of Pyruvate | Exam IV

Under an aerobic environment __ can be established from pyruvate.

acetyl CoA

Pyruvate is transported from the — to the — via —.

cytoplasm; mitochondria; facilitated diffusion

Pyruvate is transported through the outer mitochondrial membrane via a —

porin

pyruvate transported through the inner mitochondrial membrane via —

pyruvate translocase

pyruvate translocase is a —

pyruvate-H+ symporter

acetyl CoA forms via an — reaction

oxidative decarboxylation

acetyl CoA formation is —

irreversible

write the net reaction for acetyl CoA formation

pyruvate + CoA + NAD+ to acetyl CoA + CO2 + NADH + H+

coenzyme A is an activated carrier of —

acyl groups

thioester bonds are — energy and — to break

high; easy

pyruvate dehydrogenase consists of — enzymes: —,—,—

three; E1; E2; E3

the outer shell of pyruvate dehydrogenase contains

E1 & E3

the inner shell of pyruvate dehydrogenase contains

E2

E1, E2, & E3 also rely on — coenzymes (prosthetic groups)

CoA, NAD+, FAD, TPP, lipoamide

coenzymes are small organic molecules derived from —

enzymes

5 coenzymes for pyruvate oxidative decarboxylation can be subdivided by —

binding affinity

prosthetic groups (catalytic coenzymes) are — to enzyme and are — altered after reaction

tightly bound; not permanently

stoichiometric coenzymes are — to enzyme and are — altered after reaction

loosely bound; permanently

stoichiometric coenzymes:

CoA, NAD+

prosthetic coenzymes:

FAD, TPP, lipoamide

thiamine pyrophosphate has a — ring

thiazole

step 1 of pyruvate decarboxylation

pyruvate decarboxylated

2-carbon fragment attached to TPP

step 2 of pyruvate decarboxylation

hydroxyethyl group to acetyl group

transferred to lipoamide

step 3 of pyruvate decarboxylation

acetyl group transferred to CoA

step 4 of pyruvate decarboxylation

lipoamide regeneration

pyruvate dehydrogenase component

E1, TPP, oxidative decarboxylation of pyruvate

dihydrolipoyl transacetylase

E2, lipoamide, acetyl group transfer to CoA

dihydrolipoyl dehydrogenase

E3, FAD, lipoamide regeneration

formation of acetyl CoA from pyruvate is —

irreversible

acetyl CoA that is not used in the citric acid cycle become —

fatty acids

E1 is inhibited by a — via —

kinase; phosphorylation

the kinase for E1 is regulated by

NADH, ATP, acetyl CoA

high — allosterically activate the kinase for E1

NADH, ATP, and acetyl CoA

E1 is activated by —

phosphotase

high — allosterically activate the phosphotase for E1 (not directly from these… via signal tansduction pathways… tissue-specific)

ADP & pyruvate

MUSCLE: tissue specific activators of phosphotase: release of —

Ca2+

LIVER: tissue specific activators of phosphotase: excess of —

insulin