Phase one - Metabolism Flashcards
(24 cards)
What are the 2 types of enzyme systems
1 Microsomal mixed function oxidases
2 Non-cytochrome oxidising enzymes
What are in Microsomal mixed function oxidases
flavoprotien, NADPH-monooxygenase
cytochrome p450
What are in Non-cytochrome oxidising enzymes
xanthine oxidase
alcohol/aldehyde dehydrogense
What are the 4 types of reactions
aliphatic hydroxylation
oxidation
reduction
hydrolysis
General equation for aromatic hydroxylation
Aromatic + oxygen and NADPH and H+ makes a phenol with water and NADP+
What happens in aromatic hydroxylation
CYP450 activates oxygen
one oxygen is inserted in the aromatic ring
phenol is made
What does aromatic hydroxylation enhance
water solubility
what occurs in aliphatic hydroxylation (what is the start and finish)
alkane to alcohol
General equation for aliphatic hydroxylation
alkane plus oxygen and NADPH and H+ results in an alcohol plus water and NADP+
What are the steps in aliphatic hydroxylation
CYP450 abstracts H from C-H bond in aliphatic chain
oxygen is inserted to form alcohol
product is hydroxylated metabolite
Where does aliphatic occur
at the ultimate or penultimate carbon
general equation for Epoxidation
Alkenes results in epoxide that results in 3 membered cyclic ethers
Epoxidation is so reactive that it undergoes further reactions such as
Hydrolysis with water
List 2 characteristics of epoxides
highly reactive electrophiles
form covalent bonds with DNA/proteins
What happens during epoxidation
CYP450 activates O
one oxygen is transferred to the C=C
a reactive epoxide ring is formed
What is dealkylation
the removal of an alky group from N,S and O
What is oxidative deamination
Amine group removed involving introduction of oxygen making an aldehyde/ketone and releasing NH3
2 steps of oxidative deamination
oxidation
loss of NH3
In oxidative deamination what increases due to the addition of oxygen
their oxidative states
NAD+ oxidations acts as what
Coenzyme
Ethanol becomes acetaldehyde via what
alcohol dehydrogenase
acetlydehyde reacts further to acetic acid via
aldehyde dehydrogenase
How does lycopene cause grapefruit colour
having a long chain of alternating C=C causes all but longest wavelengths to be absorbed
How does grapefruit affect medicines
Furanocaumarins inhibits CYP3A4 which is responsible for breaking down drugs increasing its conc in the bloodstream
