1) Alcohol Metabolism & Oxidative Stress Flashcards
(23 cards)
Which organism metabolises alcohol?
Liver
Roughly how muc alcohol is metabolised?
> 90%
How is non-mteabolised alcohol removed from the body?
In your urine
Through your breath
What enzyme oxidises alcohol?
Alcohol dehydrogenase
What is formed when alcohol is oxidised?
Acetaldehyde
NADH
What enzyme oxidises acetaldehyde?
Aldehyde dehydrogenase
What is formed when acetaldehyde is oxidised?
Acetate
NADH
What is acetate converted to?
Acetyl-CoA
What enzyme can oxidise smaller amounts of alcohol?
Cytochrome P450 2E1
Catalase (in brain)
What is the recommended maximum alcohol intake?
14 units per week spread over a minimum of 3 days
What is the rate of alcohol metabolism?
7g per hour
Zero order kinetics - rate of alcohol metabolism remains constant even if more alcohol is consumed
How does liver damage occur due to alcohol?
causes acetaldehyde to accumulate
causes a build up of fatty deposits
causes liver cirrhosis
Does aldehyde dehydrogenase have a high or low Km for acetaldehyde?
Low Km - reacts quickly/readily with acetaldehyde to keep it at a low level
What is disulfiram used for?
Treatment of chronic alcohol dependence
How does disulfiram work?
Inhibits aldehyde dehydrogenase causing a build up in acetaldehyde
Acetaldehyde causes the symptoms of a ‘hangover’, so disulfiram causes people to associate alcohol with being sick s
What is oxidative stress?
A disturbance in the balance between cell defences (Antioxidants) and cell damage (ROS & RNS)
What are free radicals?
An atom or molecule taht contains one or more unpaired electrons and is capable of independent existence
How do radicals cause damage?
Free radicals are very reactive and aquire electrons from other atoms, molecules or ions, which typically generates another radical
What is the structure of oxygen in terms of unpaired electrons?
Biradical - 2 unpaired electrons in different orbits
How does Superoxide form?
By adding another electron to molecular oxygen
How does the ‘hangover’ feeling arise?
Acetaldehyde accumulation
Dehydration via ethanol as it inhibits ADH secretion
How does alcohol metabolism produce energy?
Acetate can be converted into acetylene-CoA which can be metabolised in the TCA or used in fatty acid synthesis
What causes a change in liver metabolism?
Excess NADH
Excess Acetyl-CoA
