Metabolism Flashcards
Coenzyme A
Adenosine 3’ phosphate 5’ diphosphate
Pantothenic acid
B-Macaptoethanol
SH= reactive part
Coenzyme A + acetyl group = acetyl coA
Breakdown of ethanol (hangovers)
Ethanol (alcohol dehydrogenase, NAD+-NADH) –> Acetaldehyde
Acetaldehyde (aldehyde dehydrogenase NAD+ - NADH) –> Acetate
Antabuse –> treatment of alcoholism
Ethanol is in direct contact with lactate (lactate to pyruvate) therefore ethanol ingestion tends to prevent gluconeogenesis from lactate in the liver
Cori Cycle
Lactate to glucose (in liver) Gluconeogenesis
Glucose to lactate (exercising muscles)
Liver produces glucose for exercising muscles from lactate
Pyruvate dehydrogenase complex
VERY BIG: 5x106 Da (60pp chains)
Requires: Thiamine pyrophosphate (TPP) VB1
Lipoamine
Flavin adenine dinucleotide (FAD) Vb2 riboflavin
24 Pyruvate dehydrogenase (TPP: oxidative carboxylation of pyruvate)
24 Dihydrolipoyl transacetylase (Lipoamide: transfer of acetyl group to CoA
12 dihydrolipoyl dehydrogenase (FAD: regeneration of oxidised lipoamide)
B1 deficiency (beri beri)
Weakness and fatigue, increase in pyruvate
Pyruvate NOT being metabolised
Krebs cycle (reactants)
Acetyl coA + Oxaloacetate --> Citrate Cis-Aconitase Isocitrate A-Keta glutarate Succinyl CoA Succinate Fumarate Malate Oxaloacetate
2 mobile e- carriers
Coenzyme Q
Cytochrome C
Membrane bound complexes
NADH-Q-reductase
Succinate- Q- reductase
Cytochrome reductase
Cytochrome Oxidase
How does cytoplasmic NADH get access to the respiratory chain?
Glycerol phosphate SHUFFLE
Inner mitochondrial membrane is not very permeable to NADH
NADH (cytoplasm) + FAD (mito) –> NAD+ (cyto) + FADH2 (mito) –> 2xATP
NADH could potentially make 3ATP but makes two; NADH in wrong compartment
Dihydroxyacetone phosphate, Glycerol 3-phosphate
Net yield per glucose:
+46ATP
Theoretically 38 but 2 NADH in wrong compartment
Brown adipose tissue
More rare than white
Mitochondria largely ‘uncoupled’ however some still are to make some ATP to keep the cells alive
Energy released as heat rather than captured as ATP
Important for maintaining body temp (thermoregulation)
Proton gradient dissapated: generates heat
Especially important in neonates and hibernating animals
Dinitrophenol is an uncoupler
Can carry H+ across membranes; uncouples white mitochondria
