Term
| NADH deh(NADH-q reductase) Flavoproteins |
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Definition
Prostetic groups of NADH deh: FMN(flavin mononucleotied) FAD(flavin adenine dinucleotide)
Flavoproteins have Fe-S clusters. (single e- carrier) 2 electrons and 2 protons pass onto prosthetic gorup |
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Term
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Definition
e- carriers containing Fe-porphyrin as prosthetic group Similar to heme but Fe undergoes valance change.
Heme in c/c1(IV) attached to S of proteins
Heme in a/a3 attached non covalently to membrane lipids |
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Term
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Definition
Highly diffusible in lipid membrane.
Carries 2 hydrogens. Functions as single e- carrier by forming free-radical intermediate.
Some e-can escape and form O2-(superoxide) |
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Term
Which complexes have Fe-Clusters?
Pump H+?
Ox phos |
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Definition
I,II,III have Fe-s clusters to accept then pass e-
I,II,IV pump protons into intermembrane space. I/III 4H+. IV = 2H+
NADH = 10H+. FADH= 6h+ |
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Term
NADH-Q reductase complex I
(NADH dehydrogenase) |
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Definition
Contains FMN,FAD and several Fe-S centers
e- pass form NADH -> FMN -> Fe-s -> CoQ
NADH -> NAD+ |
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Term
| Cytochrome C reductase(Complex III) |
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Definition
Contain cytochrome b, Fe-S, Cytochrome C
e- pass from Co-Q(ubiquinone -> cyt B -> Fe-S -> Cyt C
Cyt C moves along intermembrane space to complex IV |
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Term
| Cytochrome Oxidase Complex(complex IV) |
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Definition
| Two heme near 2 Cu atoms clamp O2 during reduction to H2O Extremely high O2 affinity and activity Cu required* |
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Term
| Succinate-FAD dehydrogenase(complex II) |
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Definition
Reduce leakage of e- away from CoQ
Entry point for FADH
Succinate dehydrogenase and glycerophosphate shuttle bypass complex I and utilize FADH2 instead
FADH = 2 atp. NADH = 3 atp. |
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Term
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Definition
Makes 3 ATP per turn.
Rate of Ox phos limited by availiablity of ADP
No allosteric control of Ox Phos |
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Term
| Nucleoside diphosphate kinase |
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Definition
ATP donates Pi to create triphosphates
GTP-Signaling
UTP-Activates sugars
CTP-activates sialic acids(NANA) |
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Term
Inhibitors of Ox Phos
Rotenone
Barbiturates
Antimycin A
cyanide
CO
Aresenate |
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Definition
Rotenone: inhibits e- flow from Fe-s complexes to ubiquinone(I)
barbiturates: Inhibit e- flow through NADH-Q complex(I)
Antimycin A: Blocks e- flow through cytochrome C reductase(III)
Cyanide: Inhibits by binding to Fe+++ in cytochrome a/a3
Co binds to Fe++(IV)
Arsenate: competes with Pi on Pi transporter and pi binding site on atp synthase |
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Term
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Definition
Pentachlorophenol and 2,4 ditrophenal
Blocks ATP synthase
Elevated NADH oxidation and O2 consumption -> hyperthermia
Allow some H+ across inner membrane (protonophores)
Billirubin also uncouples: brain damage in infants. |
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Term
| Functions of pentose phosphate pathway |
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Definition
Create
NADPH: reductive biosynthesis
Ribose-5-phosphate: nucleotides
Sugar-phosphates
Very active in RBC. NADPH needed to protect against ROS. (NADH however still reduces Fe+++ in methemoglobin) |
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Term
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Definition
1st step in Oxidative phase of pentose pathway.
G-6-P -> 6-phosphogluconolactone + NADPH
Oxidation
NADPH is an potent allosteric Inhibitor
(major regulatory step) |
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Term
| 6-phospho-gluconate dehydrogenase |
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Definition
3rd step in Oxidative phase of pentose phosphate pathway.
6-phospho-gluconate -> ribulose-5-phosphate + NADPH + CO2
Oxidative decarboxylation
NADPH is an inhibitor |
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Term
Transketoloases
(non oxidative phase of Pentose P pathway) |
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Definition
Transfer 2-carbon keto groups(TPP)
Require thiamin pyrophosphate(TPP) Covalently bound to enzyme via schiff base(C double bond to NH2 of lysine)
X-5-P + Ribse-5-P <-> G-3-P + Sedohehptulose-7phosphate
X-5-P + E-4-P <-> G-3-P + F-6-P
Xylulose donates the carbons |
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Term
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Definition
Requires no coenzymes
Sedoheptulose + G-3-P <-> Erythrose-4-P and F-6-P
Sedoheptulose donates 3-c aldo fragment |
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Term
| Wernicke-korsakoff syndrome |
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Definition
Transketolase Defect
Mutation reduces affinity for Vit B-1 in transketolase(No TPP)
Vitamin/coenzyme deficit can make a normal, but essential equilibrium rxn rate limiting. Normal pathway function and control lost.
Malnourished alcoholics |
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