Chapter 18 - Pyruvate Dehydrogenase Flashcards
1
Q
3 stages of cellular respiration
A
- acetyl CoA synthesis
- citric acid cycle
- electron transfer/oxidative phosphorylation
2
Q
acetyl CoA
A
fuel of citric acid cycle; major source of metabolic energy
3
Q
pyruvate dehydrogenase complex (PDH) present it..
A
mitochondria
4
Q
cofactors
A
- helper molecules
- non-protein, usually made up of vitamins
- bound to an enzyme
- required for catalysis
- do not catalyze
5
Q
PDH cofactors
A
- thiamine pyrophosphate (TPP)
- lipoic acid
- coenzyme A
- flavin adenine dinucleotide (FAD)
- nicotinamide adenine dinucleotide (NAD+)
6
Q
how does Coenzyme A attach to things?
A
reactive thiol group
7
Q
TPP is derived from..
A
vitamin B1
8
Q
Where does TPP bind to PDH?
A
E1
9
Q
TPP to acetyl CoA
A
accepts 2 carbon backbone after decarboxylation to result in hydroxyethyl TPP intermediate
10
Q
lipoid acid role
A
bind to E2; accepts hydroxyethyl TPP to form energy-rich thioester bond
11
Q
NADH and FADH2 roles
A
electron carriers; carry 2 e-
12
Q
oxidized form of lipoid acid
A
disulfide bond
13
Q
reduced form of lipoid acid
A
hydrogenated sulphur
14
Q
acetylated lipoid acid
A
1 hydrogenated, 1 attached to acetyl group..?
15
Q
Summarize PDH and synthesis of Acetyl CoA
A
- pyruvate converted to acetyl CoA by PDH complex
- E1: oxidative decarboxylation of pyruvate and transfer of 2 carbon unit to E2—> hydroxyethyl TPP
- E2: transfer of acetyl moiety to CoA to synthesize Acetyl CoA
- E3: regenerates oxidized lipoid group of E2 and transfers protons and e- to FAD and then NAD+ to complete cycle
