Detoxification Pathways in the Liver Flashcards
How are dietary toxins directed to the liver?
Via the portal vein
What size chemicals does the cytochrome P450 system oxidise?
Mr < 5000 - bigger than this will be dealt by the immune system
What is the nomenclature for cytochrome P450?
CYP family, subfamily, form e.g. CYP2A6
Where are cytochrome P450 located in vivo?
in endoplasmic reticulum and mitochondria
Where are cytochrome P450 located in vitro?
microsomes
Why is the cytochrome P450 called 450?
Because that is the maximum absorbance when bound with carbon monoxide
What is the role of all cytochromes?
To carry electrons involving Fe2+ > Fe3+
What is the role of cytochrome P450 in the liver?
to alter molecules to a soluble form so they can be excreted by the kidneys
What type of enzyme is cytochrome P450?
a monooxygenase - adds an OH group to the molecule
What reaction does cytochrome P450 catalyse?
formula – won’t paste from Evernote
What is the major reaction of cytochrome P450?
hydroxylation
What is epoxidation?
A reaction that can be done by P450 which results in a substrate that is highly reactive with DNA
Does the substrate just undergo one reaction?
No - can undergo multiple sequential reactions
How is the cytochrome P450 reaction initiated?
By the binding of a substrate to P450
What is the function of the reductase also present in the membrane?
To pass one electron at a time to cytochrome P450
