week 7 - drug metabolism 2 Flashcards
What is biotransformation?
The biochemical modification of a chemical compound
What is biotransformation in drug metabolism/
It is the process in which the properties of a xenobiotic are changed from a lipophilic form (that favours absorption) to abhydrophillic form (that favours excretion)
What are the disadvantages of biotransformation?
It can detoxify or bio activate xenobiotics to more toxic forms that can cause tumorigenicity orally other toxicity
What do Phase 1 biotransformation reactions include?
hydrolysis
reduction
oxidation
exposing/introducing a functional group to increase reactivity and to SLIGHTLY increase hydrophilicity
Includes cytochrome p450
What do phase 2 biotransformation reactions include?
Sulfation
acetylation
‘methylation
conjugation
etc etc
these reactions STRONGLY increase hydrophilicity
Where is the highest concentration of xenobiotic metabolism enzymes?
Liver
lungs
small intestine
Where in the cell does most biotransformation occur?
The rough ER as the rough EWR has ribosomes attached to it to help with biotransformation
What happens in the conjugation reaction of phase 2 biotransformation?
Itr involves the conjugation of functional groups such as:
small polar groups (amino acids, sulphate, methyl
OH
NH2
COOH
It makes drugs less reactive so they can be more readily excreted by the kidney
It increases hydrophillicity
Slide 15/16
What is haem incorporated into in the bine marrow?
Haemoglobin
What is haem metabolism used for in other cells?
synthesis if cytochromes and other related compounds
What does the oxygen carrying ability of the ham molecule depend on?
The presence of ferrous iron (Fe2+) - which is present in haemoglobin
