Cytochrome P450 Flashcards
1
Q
what is cytochrome P450
A
apoprotein with prosthetic haem group
has mono-oxygenase for endo and exogenous compounds
2
Q
what are the substrates for CY2C19
A
omeprazole, diazpam, citalopram, prognanil, S-mephenytoin
3
Q
CYP2C192 and CYP2C193 are _______, while CYP2C19*17 is ______
A
poor metabolisers, ultra-rapid metabolisers
4
Q
CYP2C19*23 effects with S-mephenytoin
A
no observable changes in Km, Vmax and clearance
5
Q
CYP2C19*23 effect with omeprozole
A
increase in Km, decreased Vmax and clearance
6
Q
CYP2C19*24 with S-mephenytoin
A
increased Km, decreased Vmax and clearance
7
Q
CYP2C19*24 with omeprazole
A
no kinetic parameters, low activity
8
Q
tamoxifen mechanism in cancer treatment
A
- competes with estradiol to receptor to block promotional role in breast cancer
- decreases tumour growth factor alpha and increase sex hormone binding globulin which decreases available estradiol and decrease overall binding
- induce apoptosis in estrogen receptor positive cells
